noob installation question

My buddy just got a core 2 e4500 and a gigabyte board. I never installed a intel before. Do you install the fan and heatsink on the board before you install the mobo or after the mobo is in the case? the plastic screw things on the stock heatsink push threw. lol dumb question, but im a amd guy.
thx for the help.

I find it easyer with it out of the case my self especial if you never used the psuh pins before

i tried it out of the case and can only get two pins to stay in.
things a pain lol.
oh well ill go out and try again see if i can get it on.

pull them all out (turn to the left to pull them out) then turn right and do not push them while turning to the right. once all 4 are to the right apply TIM and push the heat sink on making sure the 4 clear parts of the pins are lined up with the holes and all the way or half the way through the hole already. then just simply press down on them is this pattern

1 3
4 2

you should hear a distinctive click when the are done correctly.