Item description:

first get your savefile from your xbox (mc2savedata.bin)
open that file with the editor
soon after you opened that file the saveslot window will show up automatically
select your slot you want to edit... the characters & the Items button will become available and you can press on one of them to go to the next screen (character for the character editor and Items for the item editor)
once done editing you can, without re opening the file again, select a different slot and edit that...
once done editing everything hit save and get your file back to your xbox and have fun ^_^

Note:
there is a Items.txt that comes with this editor
this file contains names and ID's for the items... you can edit this as needed but keep the structure or you might delete items you might want to add...
the list to add items it's generated from this file... so if you add new items that aren't in the list yet... be sure to watch your spellings...