Depends on where they are in their aviation life. If it's the 15 hr about to go solo, then simple is good - select the gliding attitude/speed, select a field in front, select flap as required. If you have any spare time/capacity switch the engine off (pump, throttle, mixture, mags, fuel or whatever). At some point a conversation can be had "if you've got the gliding speed and the ac is maintaining/gaining height then we can think about etc etc etc".