not too familiar with your particular tank but to add a sump i'm assuming that you'd need to drill and use a gl******es.com overflow or if you dont want to drill, use a CPR or eshopps style overflow box. after that, build a sump and get a skimmer. filtration can be handled by a filter sock on the drain line leading to the sump
edit-- didnt see one of your posts, after reading you have chambers i'm assuming its an AIO so maybe if you can drill the tank (bottom or side depending on whether or not its tempered) and add a dorso or herbie in the back chamber, then put your skimmer and what not below in the sump