How does it work?

Been spamming all my cooldowns for a while now
Except I dont use blood for blood when things get quite dangerous

But I do wanna learn more about how Bard Cooldowns works

Mostly I wanna know more about Barrage

Is Barrage best used with Empyreal Arrow? Or Sidewinder?

Should I use all my cooldowns at the start of a boss with Barrage + Empyreal Arrow
last?

Any info would be welcome
Tried to find some information, but all the info I could find was outdated :S (9 months+)