Auto Layout was a very mysterious tool and it felt like another programming language to learn, but I was able to learn all the mysteries with this course. Bitfountain offers a $25 video course and I completed most of the course. They teach you the foundamentals from different ways of doing constraints i.e NSLayoutConstraint, anchors, Mainstory board constraints and VFL. I think it was lacking MORE exercises for each topic, but for $25 I do think its great value.
The best investment is in yourself!!!
aaaand I just bought sketch 3 and a course on udemy.