: Use the SteamDB website to find specific manifest IDs for the version you want. You then run commands via your terminal to pull those exact files from Valve's servers.

Steam will automatically begin downloading the CS:GO files (roughly ) as an update. Downloading CS:GO as a Separate App

Downloading and installing has changed since the release of Counter-Strike 2 (CS2), which officially replaced it on Steam. Depending on your needs, you can still access the "Legacy" version of CS:GO or even download it as a separate application. How to Download CS:GO (Legacy Version)

: Once downloaded, you must add the csgo.exe as a Non-Steam Game to your library and use the -steam launch option to ensure it runs correctly. Installation Details Update & Installation Issues - Steam Support

: You need a Steam account that owns Counter-Strike and the Depot Downloader tool.