Press C to change the settings.
Player - Create a PGN from the engine of your choice, part of the engine name is enough. Type for instance stockfish and all games of all Stockfish versions will be stored in PGN format. Included in the download is the file rebel12.pgn, typing rebel was enough to filter the games of the ancient Rebel 12 and Rebel 12.01 versions. Press enter to ignore this search option.
Minimum ELO - In case of an ELO rating search -- such as the 3200 above -- all games between two 3200+ elo rated engines will be output to PGN. As examples 3200.pgn (85.060 games) and 3300.pgn (22.549 games) are included in the download. In case you want to store the whole 5 million database to PGN press enter on all search settings.
Year from | to - Not very interesting for comp-comp games but very useful for human-human databases. Press enter to ignore these 2 search options.
Text - Useful in case you want to select on CCRL or CEGT games. Most games contain the CCRL or CEGT mark or on time control, CCRL games most of the time contain the [Event "CCRL 40/4"] tag, CEGT games sonething in the order of [Event "CEGT Blitz 40/4 (2Ghz)"].
When you have finished your selections press G that will start the (below) search process.