Does anyone know what a yf (yarn forward) stitch is? I know what a yo is, but i am assuming a yf is different?
I just had to look this up my self this link might help
http://www.knitpicks.com/content/index.php/cat/glossary-of-terms/
Hope this helps 
It’s usually a YO if it’s between knit sts, but sometimes it’s just bring your yarn to the front, slip a st, then move it back to continue knitting. How’s it used in the pattern?