Ok, first copy everything from the location you downloaded it to, and paste it into the folder labeled Data the directory you installed fallout into. (Usually its C:/Program Files/Bethsuda Softworks/Fallout 3/Data" From there you can either open the Fallout Mod Manager (Download link is here), or the generic launcher and activate the .esp file. If that dose not work, simply update to the latest version of fallout (patch is here) and try to run the game again. Also make sure you look at the requirements for a mod, if it requires any of the DLCs and you don't have them, get the DLC(s) or the mod will not work, causing crashes, or odd things like missing weapon and armor parts.