Problem with minecraft sdk gun mod?

Ok I just recently installed the sdk gun mod for minecraft and i ran the game and in game i made a weapon and what happend when i tried to choose the weapon in my inventory the game went black. I checked the forum and it said... showAmmoBar to false in mod_SdkGuns.properties.. ok so i tryed to figure out how and i dont know how to set a thing to false so please explain.