adafruit industries

I'm a perfect beginner.
I got an old xox, it's about 10 years old. And I want to change its firmware to MarOS 1.5
How to do it? I have a xox, marOS hex-file, USB cable, and WIN 10.
Do I need some special firmware program?
If you can give me a manual on how to do it all, I have no ideas at all.

I'd probably try this:
http://antonsavov.net/cms/projects/

and then move to the second link ("control app...").
(I'm not allowed to post the direct link because the forum software considers this as spam. Oh well.)

No idea whether W10 can still execute 32bit programs, though.