you have the proper files, but you need to burn the .iso (image file) to
the CD. Simply put, the .iso file contains all the files you need, and in
burning the image to a CD, you will not have an .iso file, you will have
boot files, setup files, installation files, etc.
"create disk from iso image" or something like that is what you want to do,
THEN boot to the CD. (also do it for CD#2, 3.. or how many ever you have).