There is a lot you can do with SSH's config file. However, this will be a brief introduction for you to get your feet wet. If you are connecting to multiple servers it may be helpful to be able to name those servers, instead of connecting to them
whoami whoami --help hostname --help | less date passwd #for setting a password su - #switch user, easiest way to switch user. # the `-` opens a login shell with the full environment of the target user. # on ubuntu systems su - doesn't work since root doesn't have
Warning: Read the whole document before making any changes. You can easily lock yourself out of the server when you strengthen it's security. I'll be using Ubuntu 18.04 for this, but what I want you to pay attention are the concepts and not so much