Tutorial:

1.  Get to the point where you want to make the stitch.

2.  Wrap the yarn twice around the hook.

3.  Insert the hook into the stitch (or chain space).

4.  Wrap the yarn around the hook and pull through the stitch (or chain space).  You will have 4 loops on your hook.

5. Wrap the yarn around the hook and pull through the first 2 of the 4 loops already on the hook.

6.  You will now have 3 loops left on your hook.

7.  Wrap the yarn around you hook and pull through the first 2 of the 3 loops already on the hook.

8.  There will now be 2 loops left on the hook.

9.  Wrap the yarn around the hook once more and pull through the remaining 2 loops on the hook to complete the stitch.

Starting a row:

Work into the second stitch of the row.  (The turning chain of 4 at the beginning of this row will count as the first stitch.