Your preset is identified by the combination of the first two fields on the left, Game and Settings. Game should be the name of your game and Settings can be whatever you want - it exists so that games can have multiple settings files (for different graphics, or because the rules change and you don't want existing games to break.) Userid must, of course, be your user ID.
Rather than starting from the Chess preset, it is often easier to start by changing a preset of a game that is close. You could open the Apothecary preset change the Game name and make any other changes you want and save it.
To make a Game Courier preset, just go into the Game Couerier editor:
https://www.chessvariants.com/play/pbm/play.php?submit=Edit
Your preset is identified by the combination of the first two fields on the left, Game and Settings. Game should be the name of your game and Settings can be whatever you want - it exists so that games can have multiple settings files (for different graphics, or because the rules change and you don't want existing games to break.) Userid must, of course, be your user ID.
Rather than starting from the Chess preset, it is often easier to start by changing a preset of a game that is close. You could open the Apothecary preset change the Game name and make any other changes you want and save it.