Create a directory to store the files Andy kindly supplied, and place the files into the directory you have created. Make a note of the directory you created and where it is located

Connect you Casio to the computer using a long USB lead and power on the Casio keyboard. The computer should make noise indicating something new has been plugged in.
Right click on the Windows Icon bottom left of your computer screen, and select Device Manager.
On my windows 10 system I got a ! exclamation mark on Other devices;- see png Before installing Casio driver picture.
I then right clicked on item with the exclamation mark and selected properties and selected Update Driver.
The system then offers you the chance to search for the correct driver your self.
So you use the browsing option to go and find the driver you placed the folder you created at the start of this process.
You do not have to select a specific file. The system just wants you to select the folder you created!
The system will now load the driver. Job done.