What is a 'bye' in a tournament?
In Swiss tournaments, if the number of players in the round is uneven, then there will be one player with no one to play against that round. This unmatched player gets what is called a 'bye'. A bye means you do not play a game that round, but still get 1 point as if you had won a game.
Who gets the bye?
The bye is not chosen at random, but instead always goes to the lowest rated player within the group with the lowest score. This way, the bye will not be likely to affect the final placings in the tournament, since the lowest rated person in the group with the lowest points is one of the least likely players to place in the tournament.