I know some readers are eager to see this typewriter in action, so here's a video that may provide some insight. I apologize for the shaky one-handed camera work, but I think it gives you a general idea of the mechanism, which is really pretty simple.
In order to work correctly the typewriter needs the guide plate, which keeps the typebars moving in a precise path -- first slightly toward the center, then up to the platen, and then back to the original position. Of course, it also needs the escapement, the carriage, etc. But in this partially reassembled state, you get the best view of the fundamental mechanism.