$ sudo apt-get update
$ sudo apt-get install opennebula-sunstone 

opennebula-sunstone is installed in your system.

Make ensure the opennebula-sunstone package were installed using the commands given below,

$ sudo dpkg-query -l | grep opennebula-sunstone *

You will get with opennebula-sunstone package name, version, architecture and description in a table

opennebula-sunstone package basic information: