Help with baby sweater, yo

I am making a newborn sweater from a vintage pattern and am puzzled about how to do a stitch. It is P 3 sts tog and leave on needle—YO—and knit in same 3 stitches. how do I do the yarn over, wrap around the needle, just pull over to other side? It makes a difference as to how it lookes on the front of the sweater. Is anyone familiar with this. Appriciate any help. Nainbach:

Just what it says, one step at a time and don’t get ahead of yourself. So p3tog, leave them, wrap the yarn over the needle (just lay it over loosely), put the R needle into the same 3 sts and knit them.