Help with a skirt placket?

I'm still working on this little dress for the grand baby. Got the bodice done except buttonholes, and now starting on the skirt.

It has an open placket and I've already misunderstood the instructions! The pattern piece shows an oval-ish line that appears to be for cutting, but it's actually for stitching, and the cut should be a straight slice between. Hence I'll need to patch something. (Zigzagging back the piece I cut out isn't working.)

(If this pattern went out of print, maybe it deserved it.)

The pattern has ONE rectangular placket piece, not two. Here are the instructions.

First, "Turn in seam allowance on one edge; press. Trim to 3/8". Got it.
"Pin placket to skirt back." It shows the placket being sewn on horizontally as though it were applied to the waistband, so I felt like a genius for figuring out that it goes on vertically to one section of the back that's split. (I haven't sewn in a long time!)

"Place seamline along stitching lines. Stitch. Trim." Which seamline and what stitching lines? Picture looks like it's kind of "outdented" away from the edge, so I could do that.

"Press seam toward placket. Turn to outside along fold line. Stitch pressed edge over seam." This picture is clear. I can do that.

"Turn left back edge to inside along seam. Press. Baste." WHAT?!? The picture shows some neat thing with a straight lower edge. There is no reference to right vs. left to this point. Again, there's only one placket piece, and oddly, it's twice as long as it needs to be. The next instructions are for gathering the waist, then attaching the bodice.

I miss my Mommy!!!

I have some extra fabric and I see there are some tutorials online. Any recommendations?

Thanks in advance!