The tournament is played on a knockout format, with 32 teams participating. Initially 24 teams play a qualification round with the 12 winners advancing to the main phase. On 29 June 2018, a drawing of lots in Luxembourg City, Luxembourg, determined the team's pairing for each match. Each team plays a home and an away match with result points awarded for each leg (3 points for 3–0 or 3–1 wins, 2 points for 3–2 win, 1 point for 2–3 loss). After two legs, the team with the most result points advances to the next round. In case the teams are tied after two legs, a Golden Set is played immediately at the completion of the second leg. The Golden Set winner is the team that first obtains 15 points, provided that the points difference between the two teams is at least 2 points (thus, the Golden Set is similar to a tiebreak set in a normal match).

The number of participants on the basis of ranking list for European Cup Competitions:

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