Download 7zip, u have to unpack the .tar.bz2. Inside there is a .XDXF file.
For the three files look here:
https://www.mobileread.com/forums/showthread.php?t=67983
In the Konvertierungsanleitung is written how the three files are made. They have infos about the characters used in the source language. its needed that the on screen keyboard gives the possibility to select all the characters necesarry to build the word. so for italian u cant just take the english character files.