I have made stack and whack quilts and the hardest part is getting all your fabric layers lined up just right for cutting. From there on, it's not hard at all. I've made the 4-patch blocks and also the 6 patch blocks (hexagons). Bethany Reynolds is a good teacher and has several books out. I'm not sure which one yours is, but some of her books are more advanced, using the technique to do more complex shapes. I hope your book is one of the beginner level ones.
Here is a video of Bethany showing how to layer the fabrics for cutting. It really helps to SEE it, rather than just read it:
http://www.quiltviews.com/bethany-s-...ck%C2%AE-video
The video moves rather fast so you might want to watch it a few times. Good luck! It's a really fun technique.