At the core of Flipgrid is the question. One of the best ways to facilitate enriched discussion is posing a great question.
If you're looking for ways to stimulate your students, check out this great guide from the Stanford Teaching Commons. Along with offering ideas on how to ensure you're asking effective questions, the guide offers suggestions on what kind of questions you should avoid.
With Flipgrid, you need not worry about the section on Managing Group Dynamics: on Flipgrid, every student has an equal voice!