How does the League of Legends ranking system work?

The ranking system starts out by assigning an initial rank to your account by providing you with 10 provisional games. Your results on these games will then automatically land you on a division from Iron to Diamond depending on your performance during the provisional games and performance in the previous seasons. You are then assigned League Points (LP) whenever you win a game and deducted LP when you lose them. Whenever you reach 100 LP you will be given the chance to play 3 games for a chance for division promotion.