Specific steps for layering two images over each other and creating one image?
 

Here are the specs. After Effects 5.5. I am trying to take to shots layering them and combining them to create one. SO the first video has me on the right and the second has me on the left. They are from the exact same camera angle yadda yadda so they match.

Does this procedure require creating a mask in individual keyframes so that the images can lay over each other in the final product?

Any help anyone can give me will be greatly appreciated. I haven't been able to find any information anywhere, here, internet, teachers....

As I mentioned in your previous thread on this topic (and we try to discourage duplicate threads at DVinfo.net), yes, your task does demand masking individual keyframes.

Since you've said you're using the Meyer book for reference, I refer you to Chapter 13, All About Masking, in particular, the section Animating a Mask. For your application, create a bezier mask on your foreground layer as big as possible and with as few nodes as possible, and feather it to taste. Adjust its nodes for the first frame, make sure keyframing is turned on, then adjust for the last frame, and as many frames in between as needed.

Depending on the choreography of your two selves, you might be able to get away with a very simple setup. For the case in which neither self crosses a center line, a single rectangular mask will suffice.

I would eyeball this and then animate it from the end to the beginning, backward.

Starting with laying out one of these clips in the final frame, duplicating that layer so now you have two layers that have the clip in exactly the same location. Then animate each of these layers separately. When you have the motion going the way you want for each layer, then reverse the keyframes so that the backwards becomes forwards.

Check out the tutorials at www.xtreme-is-back.com. He has a really good video tut on Chromakeying in AE that takes you through it step-by-step.