Probably the FAQ since it really is a frequently asked question. Maybe multiple slightly different ones.

Q: I want to play the game, how do I do that?
A: Currently you can download a LU client and the LUNI server v0.6 to get a very incomplete but mostly working server. For multiplayer servers you will probably need to wait for a public server as it is harder to set up, like the one CuzItsJonny used to provide or DLU.

Q: I want to host a LAN Server to play with my friends
A: … 0.8-dev; not recommend; vulnerable; port forwarding or hamachi.

Q: What is the LUNI Server capable of?
A: … v0.8-dev: multiplayer, chat, mail, char creation, sometimes NPC; v0.6: visiting worlds

Q: …?
A: …