To make a student the presenter, you can go to the “People” section located on the toolbar, and click the “Invite to present” icon . Once the student accepts to be the presenter, he/she will be able to share screen, draw on the whiteboard, open files, and lead the class just like a teacher
Alternatively, click the “invite to present” icon  on a student's video window while hovering over it to make a student the presenter.