need help with veg box

well I have completed my veg box it measures 36x26x18 but I have not made any holes for exhaust/intake and I obviously need to lol..
my vegroom is going to be using one 125W full spectrum
anyone have any suggestions? I have a bunch of 4" flexiduct and an induct fan (80cfm) anyone have any ideas?

Thanks.

You might wanna put a thermometer in there to check the temperature because it WILL GET HOT!
also put some c02 and air purifier,water and take care of it.
good luck.