Bootable USB from "InstallMacOSX.dmg"
How do I create a bootable USB from the InstallMacOSX.dmg file downloaded from Apple's support page (https://support.apple.com/en-us/HT208969) ?
I'm trying to create a bootable USB for macOS High Sierra in order to install on a late 2009 iMac. I am currently running macOS Catalina on my 2019 iMac.
Thank you!
iMac 21.5″, macOS 10.15