average knowledge with everything around mods and dlcs
Ok so first you'll will need dawnguard in general which can be obtained from a pirate site such as ipt or piratebay or you can pm me for the download.
Next you will need horizon.
Once you have downloaded both dawnguard and horizon open up horizon and insert dawnguard into horizon. (dawnguard is named A0D383460116AA2DD67ADFC1687EEA667B97F6FE42 in the 0200000 folder)
this is what you should get:
Extract both .bsa and .esm to a folder, you don't need the .spa file.
now put the .esm and .bsa into your skyrim data folder.
Now that you have that just launch skyrim and check the dawnguard.esm in the launcher and you should be good.
The limits are very bad.
You cannot hear/do anything that is dawnguard related which it is suggested that you should go to a isolated place such as breezehome or the wilderness before activating the dlc. also if you add a dawnguard dlc item do not open your inventory the game will crash but you can still add them via console commands and they will appear on xbox. If you're going to be modding your savegame while having the dlc make sure when you're on the xbox to unequip anything that is dawnguard related,make sure you're no where near anything that is dawnguard related,etc.
Here are the id's for dawnguard: http://http://www.game-tuts.com/comm...rd-ids-113030/