1.Put your Gamertag onto your USB/ Or Move your hard drive over to your computer
2.Unplug your USB and plug it into your computer or Connect your hard drive to your computer
3.Open Horizon
4.Now Open Your Usb or Hard Drive and Find and extract your chosen gamertag to your desktop
5.Once extracted open the Gamertag On Horizon then go on contents
6.Find and Extract your minecraft.gpd file (584111F7.gpd)
7..Open your 584111F7.gpd file into the Editor
8.Mod what you want
9.Click SaveandReplace on the editor then put the 584111F7.gpd file back into your Gamertag
10 Now your done Enjoy

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This is "easy" to do and PM me if you need help with this.