Every Merge gives you order, it has two inputs, A and B, and it merges by default A over B. You can change the merge operation. By stacking merges, you can emulate what AE does. So whatever you can do in AE, you can do here.
I believe it works very much the same way. Have a background for replacing, track the movement of what needs to be tracked, make a roto for what is to be replaced. merge. Rinse and repeat for the horse. I wouldn’t call this ‘beginner level’. You most probably need to find functions and graphs which do what you’re used to in aftereffects. Have you done things like this with footage like this in AE?