Windows NT Sliders (e.g volume control) keyboard shortcuts keys

Metro Apps are tied to System Volume and so when i'm using the Deezer ... Do Apps have their own individual volume sliders in Windows 10 or is it the same? ... What about some programs that have no volume sliders at all (E.g: Deezer), ... I just started with Deezer and I can't control my volumes for shit!

 

Shortcut                                                             Command
RIGHT ARROW or DOWN ARROW	Selects the next higher setting.
LEFT ARROW or UP ARROW	Selects the next lower setting.
HOME or END	Selects the lowest or highest setting.
PAGE DOWN	Selects a somewhat lower or higher setting depending on the application. (This is the equivalent of pressing an ARROW key many times.)
PAGE UP	Moves in the reverse of the PAGE DOWN.