Contact me directly ASAP (PM in Roll20). I have an already set-up solution that I created for this situation. It is an instructional game of Basic Fantasy with a FREE PDF rule book, made for ages 12+. I have 7 years experience on Roll20 and designed this option as a way to teach new players, starting with basics, with low expenses, and with being able to teach young GM's to start branching off their own games. I will also show your group how to generate free dungeon maps & upload them into roll20 for this. Sticking points for me: Would want to hear more about your group membership & first-names, the roster. Would want to get them all individual Roll20 logins as soon as possible, ahead of game day. Would have to discuss scheduling as I may-or-may not be able to meet with your group this coming weekend to get started. Would require their teacher, parent, or adult to be involved.