UPD TIP - IF "Map doesn't exist" SOLUTION

1. Subscribe the map!
2. For some reason Steam downloads files in the wrong folder.
In order to make it work, you need to manually copy the files from one folder to another.
3. Go to the directory:
C:\Program Files (x86)\Steam\userdata\...\ugc\referenced\SET_OF_NUMBERS FOLDER
or
C:\Program Files \Steam\userdata\...\ugc\referenced\SET_OF_NUMBERS FOLDER
4. In one of these folders find a file named as "aocsdklevels_9b42b1314324208ed930aeb9e3e8a70e.cmwsdk"
5. Copy this file to a directory:
C:\Program Files(x86)\Steam\SteamApps\common\chivalrymedievalwarfare\UDKGame\CookedSDK\__CMWSDKFiles
or
C:\Program Files\Steam\SteamApps\common\chivalrymedievalwarfare\UDKGame\CookedSDK\__CMWSDKFiles

If there is no folder "__CMWSDKFiles" create it manually.
6. Now you can start the game and open the map through the console!