We will begin by how to add a new user to your computer, after we will show how  to disable root login and use sudo instead. The reason being if something happend we can find out who has the last person who loged in.
First Open your terminal, as root type the commands:

adduser mrx
passwd mrx

After  add the  user  to the  sudo file, open up the /etc/sudoers file in your editor

nano /etc/sudoers

## Allow root to run any commands anywhere
root    ALL=(ALL)       ALL
mrx  ALL=(ALL)  ALL

nano /etc/ssh/sshd_config

#diableing login ass root
#PermitRootLogin yes
PermitRootLogin no

restart your sshd:

service  sshd  restart

if you want to know how to setup the ssh server for the first time or how to use public, private keys go here