Download an ISO file from http://www.ubuntu.com/getubuntu/download and burn to CD or install to USB key with unetbootin, if you plan to install it on a server there are two installer versions Ubuntu Server and Ubuntu Server Live .
- Step by Step installation of Ubuntu.
-  Community Documentation
-  playing proprietary formats
- Automatic Updates https://help.ubuntu.com/lts/serverguide/automatic-updates.html
Mayor changes/ Versions
Ubuntu 18.04 LTS (BionicBeaver):
- chrony replace ntpd as the recommended server for the NTP protocol.
- Some application delivered by default as snaps
snap search canonical, such as Docker, Kubernetes, microk8s, aws-kernel or azure-kernel
Canonical provides official support for Ubuntu
- Install applications using snaps
- Check your Ubuntu version:
- Learn about Ubuntu releases cycle policies: https://ubuntu.com/about/release-cycle
- Read # Learn about Ubuntu releases cycle policies: Linux_server_administration/apt/Automatic_updates