That is cute!
I haven't made that pattern. The patterns and instructions are well written. Take them one step at a time after you have read over the entire pages. I like the soft n stable product but like to keep it out of the seams. It is really thick when you have 2 layers in one seam. Be sure to stitch the edges of each piece as instructed. Again, I cut the SnS just a little smaller. The edge stitching holds it all together for you to put the binding on.
Watch all the tutorials as they have great information and reasoning on the why of doing things as certain way.
Read the binding instructions. You will want to make it bias to go around the edges. I still haven't got curves down but the process it coming along. I made the back pack last year and needed help to finish it. We have monthly classes on these patterns at the LQS so help is available.
The zippers work well. In fact, I like them the best for bags, etc. A double one can be cut and you have two for one.
I'm working on a bag today (not an annie pattern) but using many of the techniques Good luck!.
ETA: Follow the instructions for zipper placement and stitching. It hides the seam line inside the way she does them.