I wrote out these instructions for someone else and thought they might be helpful for others. The biggest thing for me was figuring out which was the apron panel and which was the leg panels, but the alternate cutting list is for a skirt, so I could tell from there which was the right one. The way I did it was

1. Mark pleats.
2. Serge edges and bottom of apron panels. Turn edge, press and top stitch.
3. Attach pants front and pants back at the side seams. (The pants back is the hinterhose.)
4. Attach pants yoke front and pants yoke back at the side seams.
5. Make pleats (this was a little challenging for me but I have pleat issues). The pleated panels are set in about 1.5-2 inches from the edges of the pants legs.
6. Lay pleated panel on top of pants leg panel, wrong side of apron to right side of pants leg. Baste along top edge.
7. Lay pants yoke right side on right side of pleated panel and sew seam (make sure you match up side seams). Press up and top stitch.
8. Finish sewing pants legs. (I did the inseam and then inserted one leg into the other. This was a little bulky because of the skirts, so I think I will try doing the front seam, back seam and then inseam next time.)
9. Pleat leg panels. Baste top edge. Sew side seams of leg panels.
10. Attach pleated leg panels to lower legs. Press toward leg and topstitch. Hem.
11. Sew band for waistband along short edge. Press open seam. Fold in half, wrong sides together and press.
12. Sew around the band one inch from top edge and leave gap for inserting elastic.
13. Insert waistband elastic, sew ends together, then close opening in waistband.
14. Line up seam on waistband with center back seam on pants. Attach waistband to pants. Press seam down, away from the waistband and topstitch.