Do you know how to burn an ISO to a disk?
Open Disk Utility. Drag the ISO into it. Click burn.
This will take the ISO (copy of the CD but on the hard drive) and burn an exact copy onto the disk.
Now insert into PC. Start it up. Enter the BIOS (F2, F10, F12, or DEL key, watch for the message. I've seen different computers with different ones, but those are the common ones). Make sure that the boot device setup is Floppy, CD, then hard drive. Exit and Save changes. Computer will restart, hopefully off of the CD.