Username...all you need to worry about is patching to 1.17. There's also a hacked in patch to 1.19, which you can find on the subforum page. I haven't tried that, but apparently it has some nice fixes. It is certainly playable with 1.17 though and you will have more available data should you run into any issues with crashes/etc.
Other than that, you really don't need to do anything else. The biggest thing to anticipate is you may run into a bug or two. Usually they will show up soon after you start playing, so you may have to search forums/etc to find a fix. Once you get it running stable, you're ready to go.
Have fun!
EDIT: Oops! Forgot about mods/documents/settings.
Mods - There weren't modding tools released. I've seen some attempts at mods, but none are essential to the game. Play vanilla.
Docs - There's the RPGdot Arx guide (again, linked on subforum page). It explains a lot. You also may need some hints via Google. The first playthrough is usually confusing at times, so there's no shame in looking for some help.
Settings - Um...set to highest/smoothest res? Not really sure what you mean by ingame settings. Configure as you would any other title.