Choose Between Guided and Unguided Shared Sessions (SPARKvue)

How do I select between leading a guided or unguided shared session in SPARKvue 2.1? When might I use each?

A newer version of this video showing this process in SPARKvue 4.0 can be found at the following link:
www.youtube.com/watch?v=5gZZ2dW2CLw