Usually when you do this type of a tournament, each player has their own index card or some other type of separate card. When a player plays another, then you write the name of each of those players on the others card. You also write "bye" on the card for any player who as received a bye for that round. You also note the round number by the players names as well. for example....on player A's card in round 1, you would write: R1, Player B....this would mean that player A played player B in R1. On Player B's card you would put, R1, Player A. That way, when you draw for round 2.....if the loser had re-bought into the tournamnet, they can't draw each other....just look at the back of the card and if they have drawn the same player, then put one back into the draw and shuffle up. You also do this for byes. If in round 1 player C got a bye, then in round 2 he cannot have the bye. No player should ever get 2 byes in a row.
You should really only allow 1 rebuy back into a tournament....that makes it two chances for them....but that is just a choice you have to make.
You also always write on that players card that they have purchased their rebuy..... that way you have a record of it. When they lose - look at the back of their card, if they have already used their rebuy, then they are done.
You can also note on the back of the card - beside each of their opponents name, whether they won/lost that match....just good record keeping.
I like to paper clip the cards for each match together while they are playing, along with a table number card. That way, you know who is playing where.
Now....when you get close to the end of a round you can go ahead and redraw for the next if you only have a match or two left playing. You would just put a card into the shuffle that says "winner of match # - in progress". That way you have a place for the winner. You can also ask both players in the match if they intend to rebuy if they lose....then you can stick a card into the draw for the loser of that match as well....if necessary.
Lots of little stuff to iron out but after you have done it a few times you will get the hang of it.
Good Luck....
Tammie