The best way to learning SNAP! is the course:

• CS10 (Fall 2015), BJC, SNAP! Lab Material on github

The SNAP! Reference Manual is good for learning all cool tricks (really, partly difficult) with SNAP!
It is not an introductory tutorial. It is a reference.

UC Berkeley Computer Science Course by Dan Garcia

It is about learning programming with the visual programming language SNAP!

• Beauty and Joy of Computing, Fall 2013, CS10 BJC home page
• Current List of topics based on SNAP!
• Run SNAP!

• Flyer (pdf)
• SNAP! Manual (pdf)
• Scratch Conference 2013 Barcelona

• Older Curriculum based on Scratch/BYOB