Sponge Filter Question

So I have a really dumb question: how do I set up a sponge/box filter? I have the filter, it's a Smallworld Filter, the airline tubing, a t-valve, and an air pump, and I hooked it all up, but I can't tell if it's working. I have a real filter on there, but it's a shrimp tank and I'm going to be moving my amanos out and putting cherries in, so I wanted a filter that wouldn't eat them
Thanks for any help!
Rachel