How do you make Halo 3 sports like grifball and basketbomb?

Answer 1

You can edit setting when you make a custom by pressing x but you need to pick something first like infection or slayer then press x and edit the settings

the way they made griff ball is they picked a normal bomb match and edited it so you start with a energy sword and a grav hammer and when you pick up the bomb you change and you can figure it out from there