You made this comment in "Xmas_90sRowHouseNeighborhood", based on your comment, it sounds like you are trying to subscribe to a collection. If for example you want to subscribe to "Ultimate Xmas collection of TTT Christmas Maps!", you most open the Collection, select the "subscribe to all" button, and then restart Gmod. After that, you should see the maps downloading upon your next start up of gmod.

None of them are showing up on my maplists