# apt-get is the package manger, installs software etc
# update, gets the latest package lists
sudo apt-get update
# upgrade
sudo apt-get upgrade
# installing a package
# ssh will be good for later so you can jump in from your other computer
# screen is like a window manager for linux, runs the server in the background
# always run an update before installing
sudo apt-get install openssh-server screen
After this you should make a new user which will run the minecraft server