find out their roles and task first, and see if they are doing their job, monitor their task, lead them to finish it at a prescribed time line. Be sure to get along well with them but maintain your distance.
You have to present yourself as an authoritative figure. If you are unsure of how you would go about this, than perhaps managing people is not your calling.
You lead lead people by example, first and foremost. Have as many group meetings as possible to make sure those that you are leading know what is expected of them.
