Ive seen some people running servers without fastdownload. Some people may not have the custom maps the lobby is running. For a example in these photos I will be using upward(you already have this)
When you find the game you want to enter go up the top and press download map.
image_one.png 332.26KB 6 downloads
If you are in chrome the download will look like this
image_2_downloading.png 23.47KB 6 downloads
After it finishes downloading go the the folder where you downloaded it and put it into your maps folder. On my computer its file directory is C:\Program Files (x86)\Steam\steamapps\common\Team Fortress 2\tf\download\maps
If its a valve map put it into
C:\Program Files (x86)\Steam\steamapps\common\Team Fortress 2\tf\maps
After putting the map in that folder it should look like this
2015-05-12_1532.png 319.23KB 2 downloads
Edited by Cookie Monster, 07 September 2015 - 10:01 PM.