Hi @dale.sykora welcome to the /e/ forum.
A reliable way to roll back is by using a Stock ROM
A word about naming convention.
Leading IMG in filename indicates an archive.zip containing other images.
The way I would look at the instructions is to complete the Pre install instructions. This is often the hardest part. One would aim to complete that before moving on to the install.
Do you have all required components? Perhaps not?
Is pre install complete?
This is a a52q forum search.