When you refer to "Simplicity" download what are you talking about ?
York used to use an OEM installed controller by that name that was just a re-branded JCI UNT1100 series device. Is that what you have or is it something newer/different ?
Maybe a picture of it ?
If it's the JCI device the "zip" file may contain 1 to 4 files with *.cfg, *.asc, *.ddl and *.prn extensions none of which are executable. If that is what you have you will need the JCI Mtools software and an interface device. Or I could be completely wrong !
If sense were so common everyone would have it !
All opinions expressed are my own. Any advice provided is based on personal experience, generally accepted fact or publicly available information. As such, it is worth exactly what you paid for it, not a penny more not a penny less !!