Could someone please post some good instructions for replacing the alternator on a 4 door 1998 Chevy Blazer please?

This may sound basic, hope is enough.

Remove Negative battery cable, remove all wires from alt , remove belt from alt, remove all bolts from alt. Replace in reverse order. A manual will give more detail perhaps.

i have to agree - pretty straightforward repair.
you might want to try the autozone repair guides. they used to be free, now you have to register on the site, but that's free, so just do it and register your car and you have access to the repair guides.