Insulating the ceiling

As I sit here and watch this youtube video: https://www.youtube.com/watch?v=h5W6shYjvhk I am beginning to wonder if I am doing my ceiling correctly. I did not put in any wood strips on the ribs of the ceiling, which would have helped me with the styrofoam boards a great deal. I have these huge gaps that I am not sure what to do with… uhm…

Back to my youtube videos I guess.