Once you unpack the .zip file, there should be one of those ubiquitous "SETUP" files parked in whatever directory you unzipped the package to. Just click on that and the machine should do all the rest.
All of these work for the older versions of Traveller, but there is nothing out for the Mongoose Version. So be careful if you are looking for Mongoose Traveller specific software.
It isn't that much different than CT. BUT, MGT includes temperature and has some Cultural stuff you can roll for. It also has options for Hard Science and Space Opera versions which are a bit more realistic than the CT version.