You will NOT get any reward for watching clips/videos on youtube. The rewards only work for live streams, and for every one live stream there is usually one encore stream a few hours later, both of which reward tokens for watching once per account. You get those tokens in intervalls of 30 or 60 minutes, so to see if you accounts are linked properly you should watch for over an hour after linking and then log in to the game, where you should get some tokens.
Also if you just want to “leech tokens”, you can open the stream in a new browser tab and mute said tab - that way you will continue to be eligible for rewards even if you browse around in another tab.
You’re welcome. 
Appreciated for the info. But damn I’m in Asia and seem like both live games and encores are run at the morning (2am~5am) for me, which is pretty suck : ( Missed out so much on these.