Change camera position

Right now, after we make a record, we just set our camera at one of the places (bottom left, top right etc.). It would be nice if I could manage it on the editing stage. For example, at the beginning of the video, I want to have a big camera on the right side of the screen for the introduction. Or even full screen without showing the record itself. But after several minutes, I would like to change the layout and make my camera as a small circle on the bottom left side.

So, my post is about changing the positions and the layouts of the camera during the editing. It would be very useful.