Or, don’t you just love making Arts & Crafts style furniture? :D
Since the back rest frame looked to be mostly square, it was time to make the back slats. I cut them to length and knocked off the end mortises.
Followed by the edge mortises in the rails, which go a little faster.
I needed to make another batch of floating tenons, then fit them to the slat and rail mortises.
This completed the major assemblies.