How to get the best effects with percocet. Take at the same time or some and then a little later, more?

Ive been in dire pain and im waiting for my doctors appt on thursday. Im taking it for the pain and it doesnt hurt to get a little buzz too. Theyre 5mg and ive been taking 3. Should i take them all at once or 2 and then like another one 30 minutes after that? And how long do they last?