Here's one simple technique:

Assuming you have the videos on tracks 1, 2, & 3, add a new empty video track above these. Place the cursor on the timeline wherever you want the angle to change and press the S key to split. When you have splits done, click on the first piece you want to use and press the [8] key on the numeric keypad enough times to move this clip to the top (empty) track. Continue this click & move process with each successive section. If you want to introduce fades or other transitions between the assembled clips on the top track, drag the edges so that the clips overlap each other (make sure you drag the edge and not the whole clip, otherwise you'll lose sync). If you decide to switch to a different angle, move the current clip in the top track back to it's original track with the numeric keypad [2] key and move a different clip back up to the top track.

When you've got the finished project assembled you can delete the three original video tracks.