Need a little help

Hello fellow reefers! I've just recently purchased a 75gal tank, with a 30gal sump, overflow and return. This will be my first big build having a sump... I want to know if you guys can just guide me through my build a little. In my 30 gallon I've got 3 sections a big one, a small one in the middle and a middle sized one at the end image of sump



Does the Skimmer go in the bigger side and the overflow spills down into the Skimmer section. Then the water pours over into the middle that would be my refugium and the spills over into the other side that has the return, return the water back into my tank?



Thanks guys! I always appreciate all the help I get from you guys!