Help!

I bought a used 75 gallon acrylic aquarium the other day, wiped and washed it down with water and vinegar to get rid of any residue or salt ( using this tank for fresh water).

Ran into the problem of filtration, I have never set up an AIO before and have no idea what goes in the back.

If anyone can shed some light on what goes where that would be awesome So I can get this sucker cycled !

P.s. should I keep the media balls ? I also took all of those out and rinsed them with a vinegar water mix.