Where to get UBUNTU ?

This is the link: https://www.ubuntu.com/desktop/developers

How to set up SSH service ?

In order to accomplish this, I'll recommend the guide from:

• http://ubuntuhandbook.org/index.php/2016/04/enable-ssh-ubuntu-16-04-lts/

Just consider to have updated your apt and installed security updates before enabling the service. Usually SSH service is the first think i put after a clean installation.