Patterns are often written this way in giving stitch counts after a bind off. As you say and GG confirms, there is a stitch remaining on the right needle after the bind off and 23sts on the left needle for the shoulder. (So each side will have 24sts.) Consider that stitch on the right needle your purl stitch and start up the pattern with a K stitch, the start of a K2P2 sequence that then repeats.
Sometimes this is just easier to see as you work the stitches on the needles. Good luck with the sweater and come back with more questions if this isn't clear or if something else comes up.