With World's in Botswana fast approaching here is a brief overview of how the preliminary rounds work.
There are 9 preliminary rounds. In each round the 300+ teams are divided into "rooms" of 4 teams with at least 3 adjudicators. In each room the teams are divided into Government and Opposition (2 teams on each side). For round 1 the draw is random. After that teams are grouped into rooms based on a system of power matching. The idea is teams will debate against other teams on the same (or very similar) points. Teams that win move up the rankings and the rooms and teams that lose move down the rankings and the rooms. Over 9 rounds this means teams should float to a level that fairly accurately reflects their ability.
Motions are announced 15 minutes in advance in large briefing halls (usually one hall for all the debaters and one hall for all the judges). The time to walk to your room is included in the 15 minutes so get there quickly and be sure to discuss the topic with your team mate along the way. Be careful not to discuss it with other teams as the rules do not allow teams to consult with other teams (or coaches) in the 15 minutes. Also electronic devices are not permitted so don't pull out your laptop or smart phone and start googling the topic. The speeches last 7 minutes each and each team member speaks only once.
After each debate the adjudication panel for the room will decide how each team did and award 3 points to the winner, 2 to second place, 1 to third and 0 to the final team. The adjudicators will also decide speaker points to each team member based on a scale of 50-100. More details can be found in the tutorial section of this site.
For rounds 1-6 there is an open adjudication. Teams are told the team points they recieved (but not speaker points) and given feedback by the experienced chair adjudicator in each room. This allows the "results" that will be assembled after each round. However as this is done by word of mouth at the championships it is not a complete list.
Rounds 7-9 are closed adjudication and the results are not announced until after the "break" on New Year's eve.
I'll provide more details on how the break works closer to the time.