I would like to perform a clean install of Mojave as outlined in this article

https://setapp.com/how-to/clean-install-macos-mojave

However, my Mac Air 2013 does not detect my usb installer as a startup disk. I have tried twice to reformat the usb as Mac OS extended Journaled and created a startup disk as outlined [here][1] , but still no luck( see screen shots below).

Most suggestions online suggest reformatting the usb (which I have already done), but it still does not pick up the usb. I have also tried rebooting in recovery mode without the usb being detected.


[![enter image description here][2]][2]



[![enter image description here][3]][3]

[![enter image description here][4]][4]


  [1]: https://support.apple.com/en-au/HT201372
  [2]: https://i.sstatic.net/i4MEE.jpg
  [3]: https://i.sstatic.net/OA18o.jpg
  [4]: https://i.sstatic.net/6gXQ9.png