The only way to download a map in a playable format is to download it in-game from blizzard. This saves the map inside a cached file within the starcraft 2 directory, there is no way to play a map that isn't in the cached file aside from the "test this map" feature in the galaxy editor. If you have a map you have created yourself, or a map someone else has created but not published, you have to open the map in the galaxy editor and publish the map and upload it (it's in the drop down menus). Then it will be available to download in-game. To download the map you have to go to create custom game, and then it will have options to list maps made by blizzard, popular maps, maps you've published yourself, and recently played maps. To find a map that is not on one of those lists, you have to know the first few letters of the map name and search for it using the search bar in the create a custom game screen. You must search exactly the correct spelling of the beginning of the map name. For example, to find "enfos bunker TD extreme" you must search for "enf" or "enfos bunker". You will never see it searching for things like "bunker TD" "enfos bunker defense", "TD extreme", "enfos TD", etc... Then you can either start a game with the map (which will of course download it first), or click the little arrow icon in the map pic to just download the map and not create a game. AFAIK there is no way to actually see what maps you have already downloaded in the create a game screen, so every time you want to play a map thats not on your recently played list or on the popular list you have to search for it again by the first letters of the map name. Because of the popularity system though, if your map isn't on the popular list anyways, there is a very low chance you'll find enough people to play it if it requires several players. Unless of course you have people on your friends list that want to play it. Personally I think this is a pretty horrible way to handle things and the convoluted hosting system just adds on to the already frustrating popularity system. Hopefully Blizzard realizes just how bad it is and will change things in the next major patch. P.S. You can also host a map that's already on the popular list just by looking it up on the join a custom game list and joining a game. If there is not a game with that map available to join, you will host a new one.