Not quite sure where to begin with my new project!

So the past few weeks my girlfriend and I have been looking on craigslist for a larger aquarium in the 150-180 gallon range to have a permanent home for our growing kids. Luck would have it we found an absolute killer deal on a setup frankly I am not sure even where to start with. I will be attaching pics to aide with this big proect we now have on our hands.

Here is the aquarium-



It's a 225 gallon aquarium. 72x24x30

This is the sump-




It's roughly 67 gallons based on dimensions 48x18x18.

The area with the bio balls is roughly 26 inches long. Does anyone know who made the sump or tank?

In the deal I also got two Iwaki WMD-30RLXT-115 mag drive pumps. I also got these pieces..



So here is my trouble. Honestly, this is significantly larger than my current setup. Right now i'm running a tank bout 55-60 gallons in size with a HOB filter. I know how to take care of fish properly, check parameters, water changes, etc etc.. The large tanks I have seen here as a lurker have been the kinds i've always wanted to get but always out of my price range. I got all of this for $300.00. I have never owned something so large. I know i'll have to purchase some plumbing pieces for this aquarium and build a stand for it. The tank is drilled on both sides of the bottom so I have to make the stand before I can even start running this setup. So where do I begin with this? What kind of sump is this? Do I need anything else major to make this happen? I have a lot to learn and plan on doing this right, so if possible some help on how do I hook all of this up. Do I need both of these pumps? I have watched a lot of videos on sumps but it's still not clicking with what I have to do.

These are some fair pics of the inside of the aquarium..




This whole setup needs a giant cleaning, lol. I appreciate any help with this. The kids can't wait to get in their new home. Thank you!

The sump is going to be directly underneath and the pumps will be in there as well. I plan on building the stand with room underneath for all the plumbing etc. The part I'm confusing myself with is this: it has dual overflows built in.. The smaller holes inside the chambers are closer to the centerline of the tank with the larger ones further away.. Are the smaller holes what gets piped up to have incoming water going towards the sump with the larger holes being piped to have the clean water exiting the sump returning to the tank? Or is it vise versa? If I'm understanding correctly each overflow has a pipe bringing dirty water to the sump and a pipe bringing clean water to the tank. Also.. These two drive pumps I have.. One motor for each overflow.

Thank you very much for the help so far, I really appreciate it. I have seen the systems running in passing but I will go to a high end lfs around here and see how they run. This week into weekend I'm going to start buying the lumber and hardware to build the stand. Is there anything else though (major components) besides basic pipes and hoses I will need to get this system running? Ie- canister filter, another pump etc? Thank you.