Can someone explain them to me? I dont quite understand how you play.

There are 5 points to hold and capture. Much like arathi basin if you've ever played WoW.

the more points you hold, the more damage you do to the enemies nexus.

http://i.imgur.com/f4A0u.jpg
From what I can gather you capture the nodes from the above image and push all the way into their base, you gain minions from capturing a node

You capture nodes and by doing so damage the enemy nexus. (Rather than hitting the enemy nexus like in SR).

The more nodes you have, the more damage you will be doing to the enemy nexus.

Sorry for not posting sooner. It sounds interesting

Holding the nodes themselves does damage over time to the enemy nexus score (starts at 500, game ends when one side reaches 0). The minions just go around the circle helping you capture nodes or something. There is no base for champions or minions to attack.

So I cant see a caster doing very well, while champs like jax, trynd, and teemo (shrooms XD ) will be over powered

oh and I think the 'metagame' riot might have been intending was two champs bot and three champs top, but i think a 'roamer' (someone who is constantly ganking/backdooring) could be a very powerfful roll especially since their are speed boosts