To quote Hannes: You have to copy the map (.bsp file) into the tf2 maps folder to play it. The map file is in your Steam workshop folder and the path is most likely "C:\Program Files (x86)\Steam\steamapps\workshop\content\440\1856165547" (Don't know your drive letter or Steam installation path). Go there and then copy and paste the map to "C:\Program Files (x86)\Steam\steamapps\common\Team Fortress 2\tf\download\maps". After that you can start the map using the console command "map trade_rustboro_r2b " or by using the "Create Server" option in the main menu.