Thanks for the help, I think I know how to make it now
if I will make urban skins for example I make in that actor file:
<UrbanLOD1>ica_us_rifleman_urban.chr</UrbanLOD1>
<UrbanLOD2>ica_us_rifleman_a_urban.chr</UrbanLOD2>
<UrbanLOD3>ica_us_rifleman_b_urban.chr</UrbanLOD3>
and in the Environment file:
<UrbanMap>1</UrbanMap>
instead of:
<DesertMap>1</DesertMap>