The CSS server is non-Steam so if you do not have a copy of CSS on Steam you can use 7Launcher to download a copy for free, courtesy of the Russian Federation. It is tested safe and is a download even the dumbest nuelfs can do (no torrenting required). Once you download the executable off 7Launcher's website by clicking the button in first picrel just run the .exe downloaded, follow the download wizard, and let the launcher verify the files once opened. Once it is finished verifying the game should boot when you click PLAY in the bottom right corner of the launcher (shown in second picrel). You will be able to connect to cs_soy no issue with this install. As far as I know the only things that don't work with the non-Steam copy is the server Message of the Day doesn't work and profile pics don't work, other than that its all the same.
>7Launcher websitehttps://7launcher.com/cs-source/?lang=en