It looks like you are a UK knitter, so yfwd is just a yfwd to you isn’t it? We in the USA would call it a yarn over. Right?
This is a multiple of 4+5 and will not lose or gain stitches over the row. Begin by knitting 2 together, then you will repeat the directions between the *s over the row to the last 3 stitches and then do the slightly different end directions over those stitches.
Within the *s you have “(K1, yfwd, K1) into next st” as the first step. Everything inside the ( ) will all be worked into one stitch. K1 but don’t slip the stitch off the needle, then bring the yarn to the front between the needle tips, then knit the same stitch again. Now slip if off. Then slip the next stitch (probably purlwise if the pattern doesn’t say otherwise somewhere) to the right hand needle without working it. Now K 2 stitches together, then slip the stitch that you slipped off over the 2 stitches you just knitted together (this is like a cast off stitch). That gets you to the end of what is within the *s.
When you have 3 remaining, do things inside the ( ), then slip one stitch, and then instead of knitting 2 together, you only K1 and pass the slipped stitch over that knit stitch.
Does that help?