Match WinsRank by number of wins. If ties are possible in your game, they'll be factored in as well.
Game/Set WinsGame/set refers to the sets of scores that are reported for a match. For example, in the image below, the score sets are 10-5, 8-10, 10-7, so "Player 1" has 2 set wins, and "Player 2" has 1 set win.
Points ScoredThe total number of points a participant scored throughout the tournament. In the image above, "Player 1" scored 28 points, "Player 2" scored 22.
Points DifferenceTotal points scored minus points given up. In the image above, Player 1's points difference is 6 (28 - 22), and Player 2's is -6 (22-28).
Custom (points system)Participants earn points whenever they win or tie matches and games/sets. You define how many points are awarded for each case. This is especially helpful for awarding losing teams points for their effort. For example, you might opt to award 2 points for a match win and 1 point for a set win. For the match in the image above, "Player 1" would earn 2 + 1 + 1 = 4 points, and "Player 2" would earn 1 point.
Wins vs Tied ParticipantsThis tie break looks at the match record between tied participants. For example, if Katherine and Dave are tied based on statistics but Katherine won when they played during the tournament, Katherine wins the tie break. When more than 2 participants are tied, they're ranked by the number of wins each one had against the others.
The Median-Buchholz system is used to break ties in Swiss tournaments. The value it shows is the sum of a player's opponents' scores, with the best and worst scores discarded. For example, if a player's opponents scores are 1.5, 3, 3, 5, 9, the 1.5 and 9 get dropped from the calculation, so the player's tie break value is 11 (3+3+5). You can read more about the Buchholz system on Wikipedia