Part 2: https://www.youtube.com/watch?v=k1HOiViVCxQ
Part 3: https://www.youtube.com/watch?v=nihxRWU6ygM
Part 4: https://www.youtube.com/watch?v=8sSV_E5lBW8
Part 5:
Part 6:
I actually learned a lot about the UI system by watching this