Hi sweetcookie! a noob is a new player to a game.. There's no real way of not becoming a noob, except to keep playing, and listen to the advice of more experienced players.
The people with green names are moderators of the game. They have been specially selected by the developers of the game to make sure that everyone follows the rules. You should read the Terms of Use in the help section to make sure you don't accidentally break the rules! If you do, you could be silenced for 24 hours!
I hope this helps!