In Cities: Skylines, please refer to the following for how to operate after subscribing to Cities: Skylines Creative Workshop:
Click "Library" in the upper left corner to search and find the game you want to use the Steam Workshop (here, take Cities: Skylines as an example).
Find and click "Workshop" at the top of the game details page to enter the game's Steam Workshop.
Enter the game mod you are looking for in the search box on the right.
Click to enter the mod's details page.
Click "Subscribe" to automatically download and install this mod.
One thing worth noting is: not all steam games support the Creative Workshop. Only games with the "Steam Creative Workshop" logo on the details page are supported.
