I dont know how to play this :/

that doesn't really make sense. You can't play ranked if you're new to the game, you need to be level 30. The game puts you through a tutorial so that's the best way to start, you should just play co-op until you get a decent understanding of the game and then move onto normals. After you've reached the point of understanding the games basics you should watch LS' coaching videos. That's probably the way I'd do it if I was going to teach a friend of mine how to go from complete beginner to decent the most efficient way.