sump question

[che2003]

I'm trying to get everything set up but I can't figure out my sump system it's a berlin sump with a aggressor skimmer there's 3 partitions to the sump where do I stick the return pump? plus there's a filter tube to put carbon here's the pic .
Thanks for your help
sump pictures

 

[liquafaction]

put the return pump at the end of the line. It looks like that is a skimmer, then a filter, then an empty resivor where the treated water will go. You want to pump your clean (skimmed, and filterd) water back into your tank