Hi
In VP version 3.xx you have a main sequence line labelled Video Track 1. and below Audio Track 1.
Above video track 1 is a grey area which at the start is empty. But if you drag a clip/image onto Video Track 1 you will see a second track appear in this area labelled "Drag and drop your video,text and image clips here to overlay"
Dropping or adding a clip from the media list on this track will show it then labelled as Video track 2. This is an overlay track .
There will also now be an Audio track 2 below Audio track 1
This procedure can be repeated to produce multiple overlay tracks etc. each one taking playing precedence over any they overlap.
Nat