In the recent movie Justice League, the villain of this part was Steppenwolf. I had previously heard rumors about Darkseid being the villain. (Maybe he'll come in the second installment)

So,

• Why was Steppenwolf brought first as the villain before Darkseid? Is he Darkseid's commander or something?
• He mentioned Darkseid's name in one of his speeches, what is his relation with Darkseid? (considering the speech in which he mentioned Darkseid he also mentions his mother, so I was thinking maybe there's some family relationship)