Heroic Familiar Temper Soul Crystal

So im going to make myself feel a bit better by first stating that the only stupid questions are the ones you fail to ask, so here it goes.

How exactly do these HFTSC's work. I dont want to get all click happy and mess something up as there isnt really a well explained guide on how these work. If there is a well explained guide then please link it and ill go read it while i ponder on the fact that a seemingly innocent object like this has me stupified.

Thank you.