I assume you mean how to re-flash.
https://e.foundation/get-started/
There is a section “Use our Easy Installer”
I would suggest watching a few online videos as well. For me personally,(not a suggestion) I have gotten cheap/high compatibility/older phones off of Ebay first, and used those as testers to see the process myself and get used to it.
“For me personally,(not a suggestion) I have gotten cheap/high compatibility/older phones off of Ebay first, and used those as testers to see the process myself and get used to it.”
Actually it should be a suggestion... Because it is very good advice.