I have put the zipper in the navy skirt. (It doesn't look navy at all, but that's a trick of the light.)
As usual, I machine baste the opening edges together and then pin the zipper from the inside, pinning down the middle of the zipper tape. Then I baste down the outside edges of the zipper tape, because I sew down the middle from the right (outside) side and I don't want to try to pick basting thread out from machine sewed thread.
Here's the back of the jacket showing the one large pleat. I put the jacket on Rose inside out to show it from the wrong side.
Here's a close-up of the shoulder seam. I am putting seam binding on only one side of this seam to finish it. The other side, I zigzagged to make it more sturdy for future long-term wearing, but it will be covered by the front facing so I don't need to put seam binding on both sides of the seam.
And here is where I am tonight, hand sewing the collar facing in between the edges of the front facings. I often machine sew these things but when I am trying to achieve a more couture look, I will make the effort and hand sew with tiny stitches.