SSH is the easiest way to access a remote computer not in graphical interface but in character interface.
To access a remote computer you should need the computer’s ip address & a username of the computer. Now connect using the credentials you now have. For Example:
Type the password of the user and hit enter. You now entered the user’s system.
You can logout, shut down the computer if you ssh root user. For that use the following ssh command:
Type the password of the root user and hit enter. You now entered the user’s system with full privilege.
You can shut down using poweroff command and to log out see this post.