Yes, you can do it by using "track motion". The online help has a brief section on it, but I would recommend downloading the complete manual and reading the more detailed explanation there.

Basically, you load your two videos onto the timeline in two different tracks for the same period of time, enable track motion envelopes for each track (you can click the track motion button on the left side of the track), and then use the track motion window to position and size the two clips on the screen.

If you want precise positioning and size, use the "Position" settings to manually set the exact size and x/y offsets in pixels. Take some time to learn the function of the buttons at the top of the screen, such as "lock aspect ratio", etc. Understanding how they work may save you some frustration.

Also, consider using the pan/crop function to zoom in or reposition each clip. Sometimes you just want, say, a single person in each displayed frame, and you can accomplish that by using the pan/crop tool.