Hi all,
to distribute my apps out of the Google Play store, I simply uploaded those apps to a public dir on my website.
That way, even an absolutely non-tech person could simply download the wanted app directly to his/her own device and installs it from Andoid's download manager.
On first attempt I used an FTP program to access my website, create a folder, upload my .apk file in it and then upload in the site root dir an html page, containing just a link to that apk file.
Umberto