It's a mess but it is free. It's an invalid ISO format which can be burned using ImgBurn on a PC, like the instructions tell. I'm Mac based and could normally just mount ISO files like a CD, but not in this case since it is invalid.

Once you have it burned, if you look at it on a PC with Windows Explorer there are html files for each chapter index but no top level file. I found that it gives errors when browsing but if you get through the error messages you can read the pages.

On a Mac (or Linux, it would be the same) it is a different story. The html files reference the PDF manual pages using absolute rather than relative paths. These paths are correct when run on a PC but not on a Mac, nor would it work if you copy the files to a hard disk folder on a PC.

In any case, the PDF files can be referenced directly, but they are numbered in such a way you don't know what they are or necessarily their order. Someone with the full Adobe Acrobat program could merge all of the PDF files back into a single document. I can only guess that the CD is intended to be used with some special Toyota-provided browser program, which would explain all the difficulty we are having.