My questions

I went to see Covenant but it still makes no sense to me. So I watched Prometheus again and it made a bit more sense but still confusing. 

Firstly my Prometheus questions. 

When they woke up the engineer why does Shaw go off her head and start screaming "why do you hate us"? Where does she get that idea from?

Why does the engineer at the beginning drink the goo and then die?

Where did the giant face hugger appear from at the end?

Covenant questions

Why does David kill the engineers? 

Where does he get the dust stuff to do that?

If they were going to destroy earth then he saved earth right?

Did the engineers create humanity?