Linda,

By "pairs of pairs", it just means that at each table 2 pairs of players play each other. Classic 'doubles' format if you like.

The footnote goes on to say "at the end of the tournament each player has been paired once with each player and opposed each player twice". If you ignore 'pairs' and just concentrate on the 'tables' aspect, then this is equivalent to saying "at the end of the tournament each player has sat down at a table with every other player exactly 3 times". Which is exactly what you want if tables are considered as foursomes.

Ian.