It's not strategy on a full scale.
In the beginning you have no IP so you can't buy stuff, but you get that from every game you play. You get to choose 1 hero/champion/whatever from a list of those you own and those who are free to play for the week. You won't own any and they cost a bit IP so you'll just pick a champion who you think looks awesome.
You enter the game, in 5v5, two goes top, two goes bottom, one foes mid. You control just 1 hero with 4 abilities, one passive ability and two spells you choose that can be used with any champion. When you level up you can raise one ability. Each ability has 5 levels, the last and fourth ability is the only exception since it only has 3.
It's not a strategy game on full scale like that Halo ODST or w/e it's name was. You control a single hero and try to destroy the enemy base, the enemies tries to do the same. So you fight each others and each bases minions on the way.
And cya. ^_^