Urar gmap folder, clicking on part one, it will urar all the parts .
Copy the resulting folder in:
(in XP - C:\Documents and Settings\All Users\Application Data\GARMIN\Maps) or
(in Vista, Windows 7 - C:\Users\username\AppData\Roaming\Garmin\Maps)
The map will be in Mapsource (last versions) without any other tweaking.
If you have an old Mapsource, update it or you'd need to tweak your registry inserting some keys-

Garmin Mapupdater it to download maps from Garmin if you have a valid subscription, not Noeman maps