Board Thread:Skyrim/@comment-125.212.50.98-20140224125841/@comment-5917342-20140224134004

If you mean the xx in the IDs, for example Serana's refernece ID is xx002B74, it means the load order of the mod by which the character of the item is added, in this case it's Dawnguard. Just check the Skyrim launcher or any other launcher you're using for the load order. If you still don't know the load other, just replace xx with 01, 02, 03 and so on, and keep trying the console commands.