Cutting my boyfriends hair...?

im going to cut myboyfriends hair for the first timeand have a few questions..im SO nervous but he could care less! lol

so if he gets a number 3, how far up the head do i use the clippers, at the ear? just past it? around the ears?

he wears it a little longer and kinda messy on top so i think ill be ok there. but any tips on blending the top to the clippered area?

thanks for any help you can give! i tried looking online but havent found answers to those questions...

Cutting my boyfriends hair...?

don't u dare cut that boys hair unless you are a professional!!!