You dont need anything. Your nearest GME dealer does it for you. These units are not end user programable.
They are factory programmed with a unique serial
number and that should be enough to register it if you purchased it in the same country that you wish to register it in.
However if you wish to add your MMSI or your callsign or change the country code, then the dealer will have to be involved.
Did you buy it new or used? If you got used or very cheap
, it may be stolen and if so, its serial
number may be on a stolen watchlist. Just be aware of this possibility if you have any doubt of its origin. Of course if you ever use it in anger, the serial number is transmitted and again there may be questions to answer after you are rescued