i want to run a sump or refugium but i have no idea how that works
I find the tanks with integrated sumps are really good for starting out with saltwater, it's what I did. They don't require sophisticated plumbing to set up, water never leaves the tank so they are basically leakproof. They don't have a ton of space to get creative which is the downside - for example I've got one with a HOB filter on it that I use as a refugium
JBJ makes good ones if you want to take a look at what I'm talking about.