I haven't used that exact kit, but it's similar to the Marineland Eclipse tank system. I don't care for the *filtration* system in these. The filter sits up in the hood, and the water is meant to flow across the top of a filter pad, trickle down through it, then flow out at the other end by gravity. This works until the filter pad starts getting debris clogging it, at which point the water just flows over the top of the pad and out, without every going through the filter pads. So essentially, it doesn't filter anything. But there is a biowheel where the water exits, so you'll get biological filtration at any rate. Just little to no mechanical or chemical filtration. My preference would be to get a standard glass tank and get an Aquaclear filter or a canister filter.
Other than that, you'll want an aragonite substrate, this will help with the pH which you want about 8.0. You can buy live sand to help cycle the tank faster, but it's more expensive. Marine salt, of course, and a hydrometer to measure the salinity. A water testing kit, so you can cycle the tank is a good idea.
Live rock is optional, but it adds to the biofiltration. Dry rock can be used too. You want to have a few hiding places for the fish, and rock looks better than PVC pipe. If you use live rock, technically this would make your tank a FOWLR.
Things like protein skimmers and UV are really optional for fish only tanks. The skimmer can help keep your nitrates lower, but so can regular water changes.
Everything else, filters, heaters, lights would be just like you'd use for freshwater.
And get a good marine aquarium book, in this department you can do a lot better than what the kit provides for you.