The GOTY edition has the base game and all of the DLC. The DLC comes on it's own disc with it's own installer. After installing the base game and DLC, I would recommend disabling Mothership Zeta. (Besides being silly; it seems to increase the frequency of crashes in the game). Afterward go to Bethsoft.com and download the Patch, and the GECK, and the patch for the GECK, and you're set. (You could also Download Nifskope while you are at it)