First, you open the installer. download at http://www.minecraftforum.net/topic/94310-125-single-player-commands-v322-official-download/page__hl__single .

Next, make sure you have modloader no forge or modloadermp Delete meta-inf.

Last, click install 3.3.2 open minecraft THAN YOU HAVE IT! for a test type

/noclip than your done. thank you for reading. P.S if you had no modloader you cant do achievments to get all achievements. Get mod loader. Cant understand? watch video down below.