Tournament Pairings

I've been asked a question in a tournament for which I am the TD about how pairings are determined.  I don't know, but think it might be that in the first round pairings are made by order of registration, and in subsequent rounds pairings are random.  Is this right?

Chess.com isnt using the swiss pairing system yet, are they ? 

On the right hand side of every tournament page.

http://www.chess.com/tournaments/help.html

"How is seeding and group placement determined in multi-group tournaments?

For multi-group tournaments, players are placed into groups starting with the highest rated player sequentially down to the lowest rated player. For example, in a 25-player tournament with 5 groups and 5 players in each group, the top rated player goes into Group #1, 2nd highest rated player into Group #2, 3rd highest rated player into Group #3, and so on. After all groups have one player, it starts all over again at Group #1. So, in this example Group #1 would have the following seeds: #1, #6, #11, #16, and #21. This is done to try and ensure that in the final round, the best players will be left playing for the tournament win."

Note groups are formed from the lowest to highest, opposite to the description of highest to lowest.

Thanks all.