SSH isn’t just the “Window” to your server. It talks with your server and lets you see what you are doing on your server. When you log in through Putty/ssh or other ssh (protocol, like ftp or http) client you are dropped in something called your “shell” - it’s like CMD but it’s for a machine running linux. Usually this is a program called “bash”.
Type “man” for a little help.
Type “man” and then a command name for help with that command.
Type “man -k keyword” for an idea of the commands that you can put after man for more details.
Beyond that - Google like the wind.
Have fun and remember that if you do anything really HEAVY you might be affecting the other users on your server.