My Apple is flashing a question mark on a folder. What do I do please?

..There's an Apple support article which covers this issue..

• If your Mac starts up to a question mark - Apple Support

https://support.apple.com/en-us/HT204323

"A folder with a flashing question mark means that your startup disk is

no longer available, or doesn't contain a working Mac operating system."

1. If the question mark appears only momentarily before your Mac starts up normally:Reset NVRAM.
2. Make sure that your preferred startup disk is selected in Startup Disk preferences.

IF the question mark persists, follow these steps:

1. Press and hold the power button on your Mac for up to 10 seconds, until your Mac turns off.
2. Turn on your Mac and immediately press and hold Command (⌘) and R to start up from macOS Recovery.
3. While in macOS Recovery, use Disk Utility to repair your startup disk.
4. If Disk Utility found no errors or repaired all errors, reinstall macOS.
5. If you still need help, please contact Apple Support.

[If your Mac is M1 Apple silicon: has other tools than intel-based mac.

Learn about macOS Recovery on Mac computers with Apple silicon.] 

With a successful start into 'internet recovery' those tools

should become available to run and install new macOS.

If an incorrect partition on the APFS was chosen, the effort

would fail. Since choosing 'less than a parent partition' won't

affect those others. And all older partitions won't be erased.

Since from an undetermined distance, few can tell what your

Mac has/had done; you may have to try and contact an AASP

or if otherwise, Apple store's Genius; IF open for appointments.

As there's a lot going on; and not all 'have luxury' of holidays.

Good luck & happy trails! ☺︎

The question is: How to get the OS on a machine that has had the disk wiped? The answer does not seem to exist.