When you subscribe, it downloads and installs in the right place. It’s strange that it didn’t work. Were you able to fix it with the Antlion mod?
Testing it in my game, when I subscribe, the mod is already installed.

In the Workshop tab under the game’s properties, does the mod show up there?

In the “Show advanced options” menu, set it to “find best order” so it will automate the load order of the mods.

Did you have this problem with other Workshop mods?

install instructions? It does not work nor appear in game workshop