It's actually pretty easy, but as Code mentioned, time consuming if you want to make an effect similar to the ones used in that video. You CAN do the camera movement thing with track motion (it'll be one of the buttons on a video track, to the left) but it'd be easier by simply panning in "event pan/crop" ( right click on a video clip or click on the crop sign on the right side of the clip). Masking will be necessary, too, if you want to make it look like characters are in the same scene. You can do that also in the event pan/crop window, just check the box at the bottom left where it says "mask".
Hope this helps, good luck