Noob to shotguns. Got an 870 Tactical in jail, now what?

[Flyin Brian]

Let me start off by admitting I don't know crap about shotguns. I finally decided to change that and see what I am missing. I found a nice 870 Tactical for sale, new, and got it sitting in jail now while I "cool off" lol. I don't think I will be adding anything to the gun, except maybe a shell holder and maybe a sling. Is there anything else I should be looking for? I have a 12 gauge brush but no jag, what's the best way to clean a shotgun bore?

What's the best way to practice for HD use? Should I be shooting a few boxes of slugs at regular bull targets or shooting buckshot or some other sized shot at clay pigeons or? Yes, I am lost in this area :-)