I'll show you a pic below with my sump/fuge empty and full. Left to right in mine.....
Water return chamber with skimmer pump & UV
pump & rubble (to help break up bubbles), baffles, fuge (miracle mud and sand, rock rubble, critters, tube worm, some rouge coral), baffle area with rubble, and return pump/UV
I'd suggest getting all your pumps on hand to ensure your build has enuf room for the pumps and hoses connected to'm, prefilters (if used), and got room to pull'm out for service. I actually had to shorten the intake and cut down the prefilter to fit one of mine in there next to another.