The different ways of doing the yarn over depend on the stitch that follows the yarn over (or yarn forward). In your case, the next stitch is a k1 or k2tog (the slip one doesn'tt require working into that stitch). Your first way of doing it is right, bring the yarn forward between the needles and over the right needle. When you do the next knit stitch, that will require taking the yarn to the back to complete the yarn over. You would only come round the needle if the next stitch were a purl.