I would have a look at e.g. Bob Harper's homotopy type theory lectures. In the 2nd lecture on Judgements, he goes through it at about 50 minutes in.
http://www.cs.cmu.edu/~rwh/courses/hott/
And Andrej Bauer's paper/lecture on "5 stages of accepting constructive mathematics"
I would have a look at e.g. Bob Harper's homotopy type theory lectures. In the 2nd lecture on Judgements, he goes through it at about 50 minutes in.
http://www.cs.cmu.edu/~rwh/courses/hott/
And Andrej Bauer's paper/lecture on "5 stages of accepting constructive mathematics"