That is really beautiful!
I did one similar a few years ago only it was an owl. I watched Eleanor Burns take a cross stitch pattern and do this. She used gridded fusible. I cut out a lot of one inch squares and ironed them to the fusible grid. Then you just do all the horizontal seams then you do all the vertical seams. The hardest part was cutting all the squares and of course the counting! The one inch squares turned into 1/2" finished squares. The unfinished owl took up my entire six foot dining table! But then, it shrunk to half that size after all the seams were sewn.
I will see if I can find the video.