This is how I did this stitch. It is not copyrighted to me. I do not own it. I just used it and made pictures of it as I went, to help clarify how it's done. Click the picture to be taken to a larger view.

First foundation single crochet stitch

 Ch 2 {picture 1} 
 
 insert hook in 2nd ch from hook {picture 2} 
 
 yo and pull yarn thru stitch (2 loops on hook) {picture 3}
 
 yo and pull yarn thru 1 loop on hook – chain made – (2 loops on hook) {picture 4}
 
 yo and pull thru remaining 2 loops on hook – sc completed – {picture 5}
 

Second and subsequent foundation single crochets

 insert hook in chain {picture 6}
 
 yo and pull thru chain (2 loops on hook) {picture 7}
 
 yo and pull thru 1 loop on hook  -- chain made – (2 loops on hook) {picture 8}
 
 yo and pull thru 2 loops on hook – single crochet made {picture 9}