Can someone explain how ratings work ?
How does it differ for L1 and L2 ?
I ask the second question because when i first went online.. I saw an open game to dominate 40 outposts.. When i tried to join, a message went something like its too dangerous and that i need 505 rating to join.. I never thought L1 were qualified for ratings.. Even if they did, theres no point since someone with L1 can't join a rated game.

L1's have no rating. If you are l1, you cannot join a rated game. If you are l2 ratings increase when you do well in games and beat players of equal or better rating. It can decrease if you do poorly, or lose to lower ranked players.

It said you needed 505 rating to join. Since you are an L1, you technically have no rating. Instead of making 2 different pop ups for L1 vs L2, they just put that anyone who isn't a high enough rating will get the "it's too dangerous" message. If I (an L2) tried to join a ranked game that was higher then my current rank, I would get the exact same message as you woul. Hope that helps