By design, during runtime we don't allow loading a configuration, since there is too much room for bugs regarding resetting things to a valid state.
So, the easiest and safest way is to have a very simple menu at startup with:
Two big buttons far apart (Load Config, Reset Config)
Label explaining to pick an option
Countdown (maybe ~3-5 seconds). If no option is picked, it defaults to Load. This is needed so that when there is a power cut, the system can resume.
If "Reset Config" is pressed, disable the countdown and ask for confirmation. No need to for a button to go back. The user can just reset to go back.
By design, during runtime we don't allow loading a configuration, since there is too much room for bugs regarding resetting things to a valid state. So, the easiest and safest way is to have a very simple menu at startup with: