I will have 3 discussion panels running at the same time and 6 plenary sessions during the 3-day event. Does the App support this kind of session separation?

Yes, Meeting Application can handle that :-)

A good idea is to create separate paths to differentiate your events. You can create dedicated paths for workshops, panel discussions, concerts, coffee breaks, etc.

Apart from that it is possible to have several rooms and days. This allows attendees to filter events in the app, so they can easily find the ones they are looking for!

The following article may be helpful to understand how it works:

Agenda - keep the most important element up-to-date