This is the tournament stage layout called Single elimination 16, it involves 16 players (or teams if the tournament is for teams):
This layout is fixed, it means that the structure of the matches has been planned from the start.
Players enter the tournament at the lines labeled "p1"-"px".
A match is where three lines in the chart meet, the two lines coming from the top and the bottom are the two players entering the match, the line leaving the T is the winner of the match.
The loser of a match may continue to another match as well, but that is written as: "m42.loser" (as the loser of match 42) rather than drawing a line from the match to the next match.