Pls go through the following tutorials in the given sequence:
Installing VirtualBox in Windows OS (if you are using Windows OS base machine)
Installing VirtualBox on Ubuntu Linux OS (if you are using Linux OS base machine which is either lower or higher than 16.04LTS)
Installing Ubuntu Linux OS in a VirtualBox
Koha installation on Linux 16.04
You will be able to successfully install Koha on your machine.