I just bought “The cat’s meow” afghan pattern. The instructions say that squares are knit separately and embroidered afterward. I’ve never embroidered. Is there a special way to embroider on knitting? Even if there isn’t a special way, how do you embroider on knitting? 
http://www.sweaterscapes.com/dup-st.htm
http://www.stitchguide.com/stitches/knitting/stitch_pages/kn_duplicate.html
Here are two sites that show how to duplicate stitch.
Thanks Ingrid! 