The best thing to do is get to the Snap! on-line editor and start programming. Snap! is VERY similar to Scratch. Any experience with Scratch will translate well into Snap! If you have the time, there are two free EdX courses, The Joy & Beauty of Computing - AP CS Principles Part 1 and The Joy & Beauty of Computing - AP CS Principles Part 2. I have found a handful of videos on YouTube, but nothing substantial. There is an official Snap! website. Here is my contribution to the effort - Snap! Instructions, which is a four page reference document I give to my students.
And how did I miss this?...Get Coding with Snap! by creators Jens Monig and Jadga Huegle.