How to start the programme and load icons on to Windows 10 store page

I must be thick today. After battling with downloading MSOffice trial pack in Kiribati and given up as they don’t have this area code, I’ve just successfully downloaded Libre 5.1. But I can’t get it to run, except to use it as the ‘open with’ option on the readme file. Perhaps I’m too tired to make sense of the instructions.