Each map is pre-generated in 5 variations. Choose any variation for maps
mc_underground
marscity2
admin
alphalabs1
alphalabs2

and place in folder maps\game

For example:

mc_underground (variation 4)
marscity2 (variation 2)
admin (variation 2)
alphalabs1 (variation 1)
alphalabs2 (variation 3)

Or do that in automatic mode by launching install_maps.bat (install_maps.sh for Linux users)!