message: drag dmg file to applications folder keeps repeating
Double-click the dmg file. A new window should open or it is already open. Access it with the Finder (either by the sidebar or the desktop) if it is already open but somehow hidden:



Now use the mouse pointer and drag the item named StellarPhoenixMacDataRecovery to the Applications folder link like indicated by the big grey arrow/the explanation above.

Open the file StellarPhoenixMacDataRecovery in your Applications folder. If you have been successful starting the application, unmount the image and delete the dmg file.