Do you want an initial animation to introduce your DVD? This is known as a Splash screen and usually transitions to the main menu. To do this you need to have a track as the first play item that jumps to the main menu.
Design a 720x480 menu in Photoshop. Make sure you don't have any active layer styles, blending modes, or adjustment layers. If you do, flatten and merge the layers . Also, make sure you are not using color management.
Import the file as a composition into After Effects.
Import any audio into the composition.
Make position keyframes for your buttons and place them at the end of your animation. Your buttons should end up in the exact position you imported them.
Animate your elements, and output your file with the Animation Codec (uncompressed audio if you are using audio).
MPEG-2 encode your track.
Import your menu and animated MPEG track into your DVD authoring program.
Select the track as the first play item.
Select the track and make the Main Menu the End Jump item.
There might be a short delay when you preview this transition in your DVD authoring application. The best way to check if this is working is to format your DVD and create an Audio_TS and Video_TS file. Open your DVD player and play the Video_TS file.