Yes, I ran the commands. I set the write permission, selected the 3rd entry option and uploaded the voucher.txt.
Trial and error?
Works for most people...
Your guest configuration is entirely wrong. It even says so in the image you posted - ie "Error: Network device is not present".
You will find many explantions of how to set up a guest network on this forum and elsewhere.
But as I said, you will get help with the voucher script on Github.