And you’re done: the OnyX for Mac is now installed.Simply drag the application’s icon to your Applications folder.Often these will include the application itself, some form of arrow, and a shortcut to the Applications folder.Double-click the DMG file to open it, and you’ll see a Finder window.dmg installation file from the official link on above Like if you wanna download OnyX for Mac from this page, you’ll directly get the. Most MacOS applications downloaded from outside the App Store come inside a DMG file.