Sorry I confused you.
On the left side of the sweater, you'll bind off 5 stitches and then knit the rest of the row.
The next row, the ws row, is purled as normal.
Now you'll start the next rs row, binding off 3 stitches at the beginning of that row and knitting the rest.
Turn and purl the ws row.
Turn, bind of one stitch and knit the rest of the row.
When you work the other side of the sweater, you'll have to do the bind-offs with the wrong side facing because that is the edge you do the neck shaping and you can only bind off at the beginning of a row.
It'll make more sense when you get to it. Just go step by step.