Single (US) or double (UK) crochet stitch

Of course, the US and the UK had to use different terms... Personally, I prefer the US terms, and that is what I use in my patterns.

Anyway, the single crochet stitch (sc) is sort of the standard stitch. The "unless otherwise stated" stitch. And luckily, it's really easy. To make a single crochet stitch, you insert the crochet needle in the stitch loops, pick up the yarn (yarn over needle) and pull through. You now have two loops on the needle. Place the yarn over the needle again, and pull the third and new loop through the other two.