How does someone get a backup playstation 1 iso to work on a playstation 1?

Well, I have a backup of my game that I converted from .mdf to .iso and burned to a disc. Sadly, it doesn't work in my playstation at all.

First of all your playstation needs to be modded in order to read the disk. If this is the case you should burn it with Nero, using the ''Save image to disk'' and enable the UDF option.