Hello JohnMcCombe
Thank you for participating in the Microsoft Community, My name is Miguel T. I'm an independent Advisor
Open Windows Settings > Update & Security > Recovery Advanced Startup and click on Restart now.
This feature lets you:
* Boot Windows from a device or disk (such as a USB drive or DVD).
* Change your PC’s Firmware Settings.
* Configure Windows Startup Settings.
* Restore Windows from a System Image.
When you click on Restart Now, it will reboot your PC, and offer you all these Advanced Options. Click, and wait till you get these options. Select Troubleshoot > Advanced Options. This screen offers further options which include System restore, Startup repair, Go back to the previous version, Command Prompt, System Image Recovery, and UEFI Firmware Settings.
To continue getting more information please follow the third party web page:
https://www.thewindowsclub.com/change-boot-orde...
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.
I hope this information has been useful, please let me know if you still need assistance.