Insert your needle into the edge of the sweater (often in the gap between stitches), wrap the yarn, and pull it through to create a new stitch.
Based on the search results, "bo st up" appears to be a knit stitch abbreviation or a fragment of a knitting pattern, specifically a "Baby Knits from Around the World" pattern involving "BO" (Bind Off) and "st" (stitch) or "pick up" a stitch. "BO" (Bind Off) and "Pick Up" Guide bost up
This sequence is often used for creating buttonholes or adding a border to a garment. Insert your needle into the edge of the
Usually, this means knitting two stitches, then passing the first stitch over the second, repeating for the number of stitches required. wrap the yarn