Bluetooth problem

[mandem]

I bought myself some earphone as fed up with my children nor returning the originals, but anyway my question is, how can I link them to YouTube via Bluetooth? As It works for Spotify via Bluetooth which I find strange anyone who can help or advice how to get Bluetooth play my YouTube play list thank you in advance 

[antikythera]

That doesn't make sense, surely you pair them to the phone/tablet and not the app. Therefore audio from YouTube should play over the headphones too