If you or your team have joined a tournament but have not been seeded (given a place in the tournament bracket) it's most likely due to one of two reasons:
You or someone else in your team didn't confirm participation during the check-in period (everyone in the team needs to do it individually) or,
You or your team were on the waiting list since the tournament didn't have any slots left (it's full). You will only get to play if one or more Ready teams drop out during the check-in period, in which case you will move up in the waiting list.
In a tournament, teams or players claim their spot in the tournament on a first-come-first-serve basis. For example, if a tournament has 32 slots, the first 32 players or teams to confirm during the check-in period will claim the spots.