how to set up my sump

[damtrees420]

so i have a 125 with a 40 gallon sump looking to get started it has a pump that sits outside the sump but drains from the botton of the sump the skimmer fits in the last chamber that the sump drains from good or bad ? and then ill have two or four chamber depending on how you look at it left one over and one under then the skimmer wondering how i should set up the rest of the sump and what i should put in it its going to be fowlr tank and i was going to have sand and live rock gest looking to start putting it all togeather this weekend plumming wise thanks for the info