How to change maps in gmod dedicated servers?

I want to change my server’s map to gm_bigcity but the dedicated server doesn’t find it in the maps folder.
I placed gm_city in my workshop.vdf file like:
“12” “105982362” //Gm_bigcity
But the file doesn’t go to the maps folder.

How can I achieve to change the map into gm_bigcity?

extract the file with this tool:
www.facepunch.com/showthread.php?t=1173875&p=38186022&viewfull=1#post38186022
then rename the info.txt to addon.txt and put it into the addon folder as usual

Ok, I’ll try it. Thanks!