Confused about sweater pattern

I’m at the last part of the back of a sweater, and I’m confused about the last line where it says to “bind off 3 sts at each neck edge once”. It says to do it at the same time. At the same time as what? The paragraph refers to 6 rows! At which row do I bind the neck edge sts?

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Bind off on the wrong side row, the right neck edge on row 2 of the 6 rows. Then on row 3, the right side row, bind off on the left neck edge. So for the neck, you’ll be binding off on rows 2 and 3.