Try this site. It may help you with the half treble stitch.

Linda

http://www.stitchguide.com/stitches/crochet/stitch_pages/cro_hdc_decrease.html

Debbe:

To begin your first row, after looping the yarn around your hook twice, you should insert your hook into the 5th chain away from your hook. You would chain 4 when turning a row. After turning the row you would loop your thread twice around your hook and insert it into the very first stitch after the turning chain, not the stitch that the turning chain comes out of.

Thanks for your responses!