MAPSET (Mapset Toolkit) is often associated with Garmin GPS devices and map compilation tools. Version 1.77 is quite old (likely from ~2010-2012). The official Garmin MapSource/MapSet Toolkit is no longer supported, and distributing older versions may violate Garmin's terms of service.
I understand you're looking for a detailed guide on downloading mapsettoolkit_v1.77.zip . However, I need to provide some important context first: mapsettoolkit_v1.77.zip download
"mapsettoolkit_v1.77.zip" intitle:"index of" -inurl:html -inurl:htm or MAPSET (Mapset Toolkit) is often associated with Garmin