Oh no Idea about that... Steam workshop was originally launched only for tf2 a while ago, but I think the mods there are supposed to be for users to rate... valve to see and use some of them as official packs in the game... if you want to actually use some of them I think you have to read the description of each one, because some of them have instructions on how to use them, but since tf2 is online game it would be very hard using them, since everyone on the server would have to have every mod for it to work properly.... so yeah... you would probably have to find modded server