Ciao,

If you right click on an empty place of the Timeline, and select "ADD TRACKS" you can add other Audio and Video tracks where you can add other clips on more layers.

How to add more layers of video with audio? Just drag n'drop your clips with audio on timeline, the "Auto Audio Bump" will place the audio clips on the next free audio tracks.

NOTE: The more layers you will use at the same time, the more processing power you will need from your CPU-RAM and GPU.

Best Regards,

Paolo