This is not so much a course in screenwriting as a series of commentaries on the process and the problems of writing screenplays of various kinds. If you want to learn how to do it, well first read something like Syd Fields "Screenwriting" and Robert McKee's "Story". There are lots of other books out there as well. Ray Frensham's "Teach Yourself Screenwriting" is the best one, if for no other reason than he came on my course many years ago and I can claim to have started him on the slippery sliding road to oblivion.
I used to teach all this stuff long before Syd Fields wrote any books about it and I probably invented a lot of the stuff people quote now as supposedly expert opinion. Personally I turned to teaching it in order to make money when I couldn't sell any scripts! So I always felt it was the illiterate leading the dumb, or something. However, in teaching it, I learned more than any of my students.
Here's lesson Number One: Writing is messy! And the end result only looks coherent and sharp after a lot of work has taken place ordering and structuring the erratic workings of your imagination.