That's new to me. For me so far it was sufficient to follow this part from the linked article...
Or, if Windows is already installed, from either the Sign on screen or the Start menu, select Power (Power button icon) > hold Shift while selecting Restart. Select Troubleshoot > Advanced options > UEFI Firmware settings.
Maybe stupid question but did you already ask in the store? I have a vegan ice cream that I buy regularly and which was sold-out most of the time. Whenever it was available I got like three or four containers. After another unsuccessful 'hunt' I just asked about it and after bringing it to their attention, they've increased the automatic re-stock quantity. It's still not available all the time but definitely more often than before.