Help With Kent Marine Bio Reef Tank!

Hi there, If anyone owns a 94l Kent Marine Bio Reef tank then I need your help! I am trying to cycle this tank to brackish for a Green Spotted Puffer that is currently in my freshwater tank. I have never done Brackish before and not sure if I have set up the pump right? It has two hoses that connect to two big pipes (I know its vague but stay with me) I am hoping to put him in there in the next week as I have put half my freshwater fully cycled tank water in and most of the fully cycled pump filter media in there as well so it's pretty much freshwater right now. I hope to put him in (as he is doing ok, sold to me in FW) Then slowly add 0.002 salt weekly to get him up to maybe 1.008? I think this is correct? Would love if someone has an diagrams as to the pump system as there is no air coming out the two pipes... Not sure if they are meant to suck in the water? But they are not doing that either? HELP lol Added pic to help me explain

They are outlet pipes and there should be a powerhead attached to the other ends inside the back chamber.

UPDATE: After numerous hood lifting and small arms down holes my boyfriend got them working! Yay thanks Ali haha