http://www.wikihow.com/Image:Install-Ubuntu-on-VirtualBox-Step-11.jpg

http://www.wikihow.com/Image:Install-Ubuntu-on-VirtualBox-Step-12.jpg

http://www.wikihow.com/Image:Install-Ubuntu-on-VirtualBox-Step-13.jpg

http://www.wikihow.com/Image:Install-Ubuntu-on-VirtualBox-Step-14.jpg

http://www.wikihow.com/Image:Install-Ubuntu-on-VirtualBox-Step-17.jpg

select your new virtual machine.

http://www.wikihow.com/Image:Install-Ubuntu-on-VirtualBox-Step-20.jpg

http://www.wikihow.com/Image:Install-Ubuntu-on-VirtualBox-Step-22.jpg

Select your virtual machine and click ‘start’ button.

-Select language and follow the instruction,and it will be done.