Honestly, and not being a wise-ass here: Read the manual that comes with it. Failing that, you can find M16/M4 mil-spec manuals online, which will have the lube specs in it, in the preventive maintenance section. And listen to the folks who’ve used it’s full-auto brother in combat.
See TM 9-1005-249-10 - Operator’s Manual for M16 and M16A1.
Chapter 3, Section I has the lubrication points and instructions.
Yep. Lightly oil the metal parts so that they shine and you can’t see a layer of oil when you rub your finger along the bolt carrier. If you can see a blob of oil in front of your fingertip when you brush it along the bolt carrier, you used too much oil.
CLP works very well.
You can also rub it on the exterior metal and plastic surfaces to make them bright.