Adding picture-in-picture (PIP) in the Multi-Camera Editor
You can add a picture-in-picture (PIP) effect to your multi-camera project. PIP lets you play a video in one area of the screen while the main video plays in the background.
The image above illustrates the concept of picture-in-picture (PIP).
To add a picture-in-picture (PIP) effect to your multi-camera project1 After you create your multi-camera compilation in the Multi-Camera track, click the Play button 
or scrub to the position in the Multi-Camera track where you want to add a PIP effect.
or scrub to the position in the Multi-Camera track where you want to add a PIP effect.2 In the timeline, click the circle on the PIP track to activate the track.
The circle will have a red fill when active 
.
.3 In the multi-view pane, click the preview for the Camera you want to use.
The segment is added to the PIP track.
4 To set the end point for the segment, in the PIP track, click the end of the segment and drag it to the position you want in the timeline.
5 To choose a corner for the PIP, click the Change PIP Position button 
on the PIP track and choose the position you want.
on the PIP track and choose the position you want.The PIP position can be seen in the main preview pane.