In After Effects the project file is the main document which references all your project assets. Whenever you start a new project, you will create a new project file to hold all of the assets for that project. When you save in AE you are saving the project file, and this is the file you will open next time you want to work on that project. The standard extension for AE projects is .aep (for 'after effects project'), and while it is not neccessary to use this extension on the macintosh it is useful to help you distinguish your project files from other files.

Within a project you will have two types of assets - footage, and compositions.

'Footage' is the term used to describe any assets you have imported into a project. These can include still images, video clips, audio files, and vector art(i.e. Adobe Illustrator files).

In AE, your footage files are not actually contained in the project file; instead they are 'referenced' by the project file. This simply means that the files exist somewhere on your hard drive and the project file knows where to find them. Because video files can be very large, referencing footage allows your AE project file to remain small. However, it also means it is possible to seperate the actual media from the project by accident. For this reason it is a good idea to keep your project and media files all in the same folder.

A composition (or 'comp" for short) can be thought of as your canvas in after effects. When you create a new composition you tell AE how big your video will be (in pixels), how long it will be (in hours, minutes, seconds and frames), and what the frame rate should be (in frames-per-second). For example, a common comp for multimedia work might be 320x240 pixels, 10 seconds long with a frame rate of 15 frames per second. A video destined for DV would have a setting of 720x480 pixels, 10 (or more) seconds long and a frame rate of 29.97 frames per second. The settings you choose will have an effect on the final output size and length of your finished video, so it is important to start your project with a good idea of your final destination.

Once you have created a blank comp you can add footage items to it to create your video. Any assets which are listed in the project window may be placed into a comp. Deleting footage from a comp will not remove it from the project, but deleting it from the project will remove it from any comp it has been used in.

Comps exist entirely within the project file and are saved when you save the project file. A single project file may have several comps within it, and you can even place comps within comps if you are creating complex videos.

The Project tab is usually in the upper left hand corner of your screen, and shows the title of the current project at the top. When you first launch AE it will, by default, create an empty untitled project for you to start working with. In the lower half of the window is a list of all assets which are contained in the project. The various columns in this list provide information about various aspects of your assets such as file name, type, size, duration, etc. By clicking at the top of any one of the columns you can sort the list according to that column, i.e. click the 'type' column header to sort assets by file type.

The column with the small color squares in it is known as the 'label' column, and simply provides a way to visually differentiate between files in the list. For instance, by default still images are labelled pink, while quicktime movies are labelled yellow. You can change these labels on an item-by-item basis in order to group footage items visually in a manner which is meaningful to you.

When you import files into a project they will be added to the list, and one shortcut for importing files is to simply drag and drop the files from a finder window into your project window.

If you select an asset from the list, a summary of it's properties is shown at the top of the project window in addition to a thumbnail image representing the footage.

At the bottom of the project tab are four buttons:

• The binoculars, bring up a search window which lets you search through the assets in your project. this can be very useful on large progects with hundreds of footage items.

• The new folder button creates a new folder in your project window. You can then drag assets into this folder in order to organize large numbers of files. This is very similar to using folders in the finder and is a great way to keep your project window from becoming cluttered.

• The third button is the 'new comp' button, and, as you may have guessed, it is used for adding a new composition to your project.

• The last button is the trash, and can be used to delete items from the project window.

The folder, new comp and trash buttons can have footage 'dropped' on them. For instance, dragging a footage item to the folder button creates a new folder and places the footage in it, dragging to the comp button creates a new composition the same size as the footage item with the item in it, and dragging to the trash button deletes the item you dragged from the project.

The Composition tab is your main workspace in AE. The area in the center represents your video, and any footage items you place in a composition will be visible here. At the bottom are several buttons which control how your composition will be displayed. We are only concerned with three of these items at this point:

• On the left side you will see the zoom menu, which lets you choose how far to zoom in or out on the composition. By default it is set to 100%, but you can change it to anywhere from 1.5% to 6400% by clicking on it and choosing a new setting from the drop down menu.

• The third item from the left is the current time indicator. This just shows you where the currently visible frame exists on your timeline. If you click on this area you can enter a new time to jump to.

• Over near the right side is a menu which says 'full'. This lets you chose the resolution to display your previews at. By default it is full, but you can also choose half, third or quarter. Lower resolutions will previoew faster, but won't show as much detail in your comp window. For small projects you can usually leave it at full, but as your projects become more complex, or if you are working on a slow computer, you may want to set it at half or lower so that you don't have to wait a long time for your previews to render.

We will discuss the remaining buttons as they become relevant to our projects, but for now you can just focus on those three areas.

At the top of the comp tab you can see a tab with the name of the comp on it. When you open more than one comp at once, each comp will have a tab in this area. This lets you toggle among multiple compositions at once without having multiple windows open.

Each composition has an associated timeline, and it is displayed in the timeline tab whenever you open a comp. The timeline tab is similar to the layers palette in photoshop; it shows all of the current layers of a composition, with the topmost layer being the front item in the composition. However, the timeline, as it's name suggests, also incorporates time for each layer. On the right side of the window each layer has a colored bar which represents it's duration. The duration bar for the currently selected layer has a slightly darker color to it, and the layer colors correspond to the label set in the project window. Across the top of this section of the timeline you can see the time, marked in seconds, and the blue arrow is the 'playhead' which points to the current frame visible in the comp window. In the upper left corner of the window the current time is displayed in hours:minutes:seconds:frames.

There are a lot of little switches, buttons and icons in the timeline window, and if you try to learn them all at once it can be overwhelming. The main areas you need to be concerned with for now are the layer names, their duration bars, and the playhead:

• To change the name of a layer, select it's name in the timeline and hit the 'Return' key. This will highlight the name and you can type a new name in.

• To change the in and out points of a layer, click on the black bracket at either end of the duration bar and drag it to increase or decrease the duration of the layer.

• To change the current frame, click and drag the blue playhead arrow at the top of the timeline. As you move it, the comp window will update to reflect the currently selected frame.

As we move into more advanced projects we will discuss the other controls as needed. For now, just get comfortable with these three basics.

The toolbar is just like the toolbar in Photoshop...you click on a button to select the tool you want to use. However, AE has far less tools in it's toolbar than photoshop, and even then some tools are used very rarely. Right now you just need to know about three tools, all of which should be familiar to you if you have worked with Photoshop before:

• The Arrow tool (leftmost button) is the most commonly used (and default) tool in AE. You use this tool to select and move footage items in the comp window, and you can drag the corner handles of a layer to scale the layer with this tool as well.

• The Hand tool (second button) lets you move your composition around in the comp window if you have zoomed in far enough that you can't see the whole composition at once.If you can see the whole composition this tool will do nothing.

• The Zoom tool (third button from left) zooms in on your composition. If you hold down the option key this tool will zoom out instead.