First you need to enable installing files from unknown sources. To do this, go to your settings, and check the box that says "unknown sources"
Now download a file manager from the google play store
Then download the APK file from my website
Next connect your phone to your computer as a media device
Then copy the APK file to your downloads folder on your phone
then open the file manager on your phone, and open the downloads folder, and then install the APK