Cannot reinstall

[hervleco]

Hello please excuse my bad English
Hello. I probably made a mistake when I tried to erase the hard drive of a MacBook Air I bought second hand.
When I tried to restart, a question mark was blinking in the center of the screen, and at the bottom there was support.apple.com/mac/startup
I used another mac to go look on the internet at the address listed, and followed the instructions.
I tried to reinstall MacOS but it didn't work (an error occurred...)

I then launched the disk utility
The problem is that in the right column of the disk utility there is a whole bunch of units that appear.
I made a picture where you can see them.
Important: The drive called Macintosh HD was not called that when I formatted it, I chose that name ( )

I first tried to delete the one on top (Apple APFSMedia) ---> Failure ("impossible to unmount the disk")
I ran S.O.S. on this unit. ---> Detection of a "damage to be repaired
---> I am advised to run S.O.S. from the spare disk.
PROBLEM: Which one is the spare drive? :huh:

What can I do? Ideally, I would like to reinstall everything to eliminate all traces of the previous owner.
Thanks a lot for your help

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[Cory Cooper]

Hello and welcome.

Try this: Use macOS Recovery on an Intel-based Mac

Let us know how that goes.

C

 

[hervleco]

It worked. Thank you!