To install this Sound Pack, 1.Extract pak005.pk4 to your doom3/base directory (IE- c:program filesDoom 3base) 2.If you already have a pk4 file named pak005, rename this pk4 file to pak006.pk4. If there is alredy a pk4 file named pak006, simpy rename this pk4 file to pak006.pk4, and so on if there's another sequential pk4 file. 3. Start up Doom 3 and the mod will load automatically.