A YO is an extra stitch. It's accomplished by bringing the yarn forward, but the knitting of the next stitch creates the YO.
If you read a pattern that, for example, says k1, yo, k1, you don't count the second k1 as part of the yo, but just bring the yarn forward so that a yo is created when you knit the next stitch.
If a pattern says yfwd and the next stitch is a knit, then it's also a yo, just worded differently.
If a pattern says yfwd, slip stitch, yb (yarn back), then you just do what it says.