By how to take it do you mean orally? If you know that you're supposed to take 2 a day than there would be directions on the bottle. It should say Take 1 pill twice a day by mouth or something like that.
There should be directions on your prescription bottles... did you double check there?
Does it say on your pill bottles? That is strange that she/he prescribed both. Perhaps to alternate? Norco generally lasts 4 hours and Percocet 6 hours. You definately shouldn't need the both at once...I would alternated until you get a call back.