1. system starts trying to find matches, with the goal of creating teams that are both made up of players with roughly equal skill and have a fair chance of winning
2. If a player is queued alone, the strength is determined by his personal matchmaking rating (referred to as MMR from here on out) and number of wins for that particular queue. If the player is queued with a pre-made team, the system will adjust the MMR of the team accordingly
3. Initially, the system will only match players with similar MMR. As time passes, the system will very slowly broaden the MMR range it considers acceptable.
New players get some special protection and are usually matched against other new players, though this may result in a longer delay before finding a game.
Eventually, the system will assemble a group of players with comparable MMRs and put the players into a game.