How to draw lots in sports competitions

Divide all teams into four different levels, from strong to weak! Then, put another group in each group of each grade; For example, if there are 32 teams, they will be divided into 8 groups in 4 grades, and each group will have a seed team, thus ensuring that the teams in the group are 1, 2, 3 and 4 grades respectively, so that the competition is the most reasonable and exciting.