Hello!

[Moab]

I am new, so I say hello everybody!But, can someone explain some multiplayer rules please?

[aldobr]

1 - Dont take anything from chests that are not yours if the owner dont tell or if the chest is not with a sign saying that you can take.
2 - Dont dig or place nodes in areas that are obviously owned by other players. (This is called grief) Not all servers have area protection and even on those that have, not all areas are actually protected.
3 - Dont attack other players unless the server is an explicit PvP server. Some servers dont allow fights even if both parties want to fight.
4 - Dont insult people.
5 - Respect moderators.
6 - Dont act in a way that hinders other players enjoyment of the game.
7 - Ask other people where you can build and mine. Be cooperative.

[Krock]

There aren't any global rules.
Most servers define their own rules because there always will be trolls which don't know anything about the normal rules.

[Minetestforfun]

+1 Krock

Welcome Moab ! Have fun !

[Moab]

Thanks aldobr,Krock, and minetestforfun