Setting up my 125 gallon fowlr tank

I am in the process of setting up a 125 gallon fowlr tank. So far I have my refugium skimmer and lighting. I also ordered my overlfow box, return pump and refugium light. Now I am trying to figure out what to do about circulation. I am not fully sure how many powerheads to get and where i should place them. If I could get some suggestions that would be very helpful.