When I was migrating from Windows, I had no clue this last step was required. This process is very different from Windows’ installer-lead process and can lead to misadventures for new macOS users. From there, users drag and drop the image’s contents into the Applications directory to install new apps on their Macs. When you double-click on the dmg, it mounts (or, more properly, attaches), revealing its contents in the Finder.
Easily identifiable by their disk-on-paper icon, the “dmg” extension stands for disk image. When you download a new program for your Mac, it often comes with a “.dmg” file.
