Can we see the back? That would give some clues?
I've found it helpful to trace the stitching lines on the fabric.
I've also found it helpful to mark the "half-way" point on each seam and pin those together.
I'm thinking that this would be a lot easier to hand sew than machine sew. Then stop at the end of each seam. Then it would be easier to press.
Also, it it a LOT more manageable with just the 1/4 inch seam allowances.