Hi and welcome!
Yes, the next directions are for the stitches that are on the holder:
"With right side facing leave center 26 (28, 30, 32) sts
on holder, join yarn and K21 (22, 22, 23). Complete to
correspond to first side, reversing shaping."
You need to slip 22sts on the left end of the held sts onto a needle and work them as the first side, reversing the shaping.
Decreasse one st at neck edge on next three rows. Bind off 9 sts at the shoulder edge. Work one row Bind off rem 10 sts.
It's a very neat looking vest that is nicely finished.