A student does not have right to speak, write or upload anything in the class unless the presenter transfers rights to the student to do so. Make sure that you have transferred appropriate rights to the student. To transfer controls to the attendee use,
a) 'Mic' icon to allow mic to the attendee
b) 'webcam' icon to let him use webcam
c) 'Pencil' icon to let the attendee write on the whiteboard or upload content in the class