I cannot install the latest version of Libre Office 7.1.3

I can download the file, but cannot install it. I get a message “This installation package could not be opened. Contact the application vendor to verify that this is a valid Windows Installer package.”
How do I verify as per this notice? How do I then proceed to install 7.1.3? Is this some kind of bastardry from Microsoft to stop people leaving?
I am using W10 on a PC, trying to get away from MS Office, which wants me to upgrade to 365 at considerable expense, currently using MS Office 2010, no longer supported, but I am used to it, and could go on with it, but believe Libre Office is a better option for me. I am an aged pensioner on limited income.

Please see my answer for question 311302

I’m having a similar problem with version 7.06 (home use) only I’m not even getting a message of any sort.