When the qualification matches end, teams will be ranked from #1 to “x” based on the ranking score criteria. The top teams then pick partners. The #1 team will pick, and they can select any team, including others in the top 8. Then the #2 team picks, and this continues until all 8 alliances have 2 teams. Since teams can pick within the top 8, often teams ranked 9, 10, or 11 become alliance captains and picking teams, so it is important to be prepared.
After all 8 alliances have 2 teams, then the pick order reverses and the #8 alliance selects a third team, then the #7. This continues until all alliances are complete. A certain number of ‘unpicked teams’ will be asked to stay ready, in case there is a breakdown and a replacement robot is needed.
Alliance selection can be exciting, but also can be a letdown for teams. Not every team can be picked (only 24 play in the eliminations). There are also times when a team in the top 8 will decline an invitation to join another team. This is legal, and may be because the declining team has a plan and strategy and the team that wanted to pick them did not fit into that strategy. Remember though, if you decline being picked by one team, you cannot say yes to another team, but you may still be an alliance captain.