Meaning of "working 1 more st in the middle"

I’m knitting my first sock ever and am up to: “Continue shaping heel wking 1 more st in the middle and decreasing 1 st on each row until all sts have been worked.” What does it mean to work one more stitch in the middle? and What does it mean to “work” stitches?

ITA :??

To work means to knit or purl as you have been doing.

I think the increase one stitch refers to making one more stitch in your short row, which will take away one stitch from the side. I’ll let one of our sock experts pick this up.