rename the map to somthing personel (example: myGoldrush.gbm )
Copy the map to your maps directory in the glest installation.
Linux( installed with loki installer in you user dir)
~/glest/maps
Windows( examples ):
C:\Programme\glest\maps
C:\Programs\glest\maps
C:\Programs\glest_2.0.1
....
Start glest and selet custom game and select your map.