Videos explaining each of the axioms and theorems and some of the proofs:
I'm missing some stuff here--if you ask for more videos, I'll make them....
Hints for theorem proofs:
Hint for theorem 4
Hint for theorem 5
Hint for theorem 6
Hint for theorem 7
Hint for theorem 8
Axiom 6 and the definition of an angle
Solid angles
The definition of congruence and what it means to be congruent angles
The big picture of theorem 11
The big picture of theorem 12
Integrating Euclid's Common Notion 5: The whole is greater than the part; and why axiom 7 is worded in the way that it is.