Jake,
To pad frames, there is an Icon on the Left side of the Timeline. Mouse over the icon and it should say
Modify Frames.
Clicking on the the Modify Frames Icon/Button will open the dialogue box where you can Add, delete, and Pad frames to your project.
You want to Pad Frames, which means to add frames without affecting the keyframes you have placed. If you understand keyframes then you understand why this is important. Since you want your animation to remain static at the end, you will need to Pad frames after the last frame.
In the screenshot I have it set to Pad 90 Frames after the last frame. That will give me 3 seconds of the animation remaining unchanged from the last frame. Padding does not move the keyframes, where adding frames does.
Hope that helps..
There are tons of tutorials around to learn how powerful this program is. Keep in mind that it is not like the big 3D Modeling programs. However you can do alot with it.