[wooler]

You need a server machine with a good enough CPU to host CS:GO servers. You can either host it yourself of use a hosting provider. I wouldn't go lower than a i5/i7. You can host multiple instances of CS:GO servers on a single box by using different ports on your server.

After you have your server, you need to download the server files with SteamCMD and configure your server.

After you have your server set up you need to install Metamod + Sourcemod for your plugins. Plugins can be found here on alliedmodders for example.