<<How do I mount virtual rails to Virtual Machine?>>

I installed virtual machine on my windows vista operating system and
am running linux ubuntu. Then i downloaded virtual rails. i created
a virtual hard disk as instructed called virtualrailz001.vdi.
whenever I try to run the virtual machine I get the following error.

Fatal: could not read from the boot medium. system halted

from what I read in tutorials im supposed to have the VM mount a
bootable ISO image to install the OS from. I cant figure out how to
mount an ISO image…I thought I was supposed to mount the vdi image
and how do I do this anyways I checked in the settings million times
and there is nothing that says MOUNT…

do you have virtual box installed? if you are using virtual box, all you
need to do is download the virtual image from virtualrails.org, and
the image as instructed on the virtual rails site. there is no need to
install anything other than virtual box.