The UEFA Champions League utilised to begin with a double round-robin group phase of 32 groups until it evolved right into a league section of 36 groups, and that is preceded by two qualification 'streams' for teams that don't get direct entry for the tournament correct. A map of UEFA https://lorenzomonmm.blogolize.com/details-fiction-and-what-are-the-uefa-champions-league-and-uefa-europa-league-75358090