Step 4Follow directions
iImage Information

Follow the directions with the installer until you get to the partitioning part, or the part where it looks like the image below. If you have a computer with nothing that you want on the hard drive, including operating systems, select guided-use entire disk. If you have stuff on your hard drive, use guided-resize..... but you are going to want to move the bar because the orange is how much the other partition will have, and the white is how much space ubuntu will have. So, to put that into english, the number above the bar is how big the other partition will have.
I highly suggest using the Live CD option. =D