Can't Install UBUNTU

[lewleib]

I am new to VirtualBox and to Ubuntu. I have a PC running Vista and am trying to install Ubuntu and then run NASA software.
In my first try I installed VirtualBox and set up a virtual computer named Ubuntu. Then I downloaded a Ubuntu ISO file. The first time wizard couldn't find the ISO file. The Second try, I downloaded the ISO file and saved it to the desktop. The VirtualBox could no longer use the first time wizard and I couldn't find CD/DVD in the menu. After reading other posts, I looked for DEVICES but didn't find them.

Please help with some step.

[waddlesplash]

Select VM -> hit Settings in toolbar -> Storage in sidebar -> click on the CD icon -> hit the CD with the down arrow to the right of the label that says "CD/DVD drive:".