macOS 10.15 Catalina is an older version of Apple's operating system, released in 2019. While it's still possible to install it on compatible Macs, users should be aware that it's no longer receiving security updates or support from Apple.
Clean installing macOS 10.15 Catalina can breathe new life into an aging Mac. Starting fresh eliminates accumulated system junk, resolves deep-seated software glitches, and reclaims valuable disk space. macOS 10
Press , enter your admin password, and type Y to confirm the formatting process. From the macOS Utilities window, select and click Continue
(Note: You must enter your administrator password when prompted.) Unmount the newly flashed volume: hdiutil detach /Volumes/Install\ macOS\ Catalina Use code with caution. From the macOS Utilities window
From the macOS Utilities window, select and click Continue.
Wait, but if they already have the DMG, they can use Disk Utility to mount it, then run the installer. But if they need the DMG itself, they might need to find a way to get it via the App Store first. So maybe the user is confused about the process.
Also, the DMG file is the disk image used to create the bootable USB. So the user might actually need instructions on making a bootable USB from the DMG or from the Install app.