case cooling for aopen hx08

i've bought 3 sunnom 80 mm's case fans for my aopen HX08 case, now my question is this, how should i place those coolers since there's one slot at the lower front and 2 slots on the upper back. which coolers should be used for air intakes, and which should remove air. i've got 2 ideas i figure that cold air drops so you'd need to get cold air in, so put the intake at the lower front and the exhales on the upper back. but then again, i also got this idea that i'd be better to get more air intake so should i swap the fans so that the 2 at the upper back are used for intakes and the lower front for exhaling, thx in advance guys