Half double crochet (hdc)

To do a half-double crochet. At first, make a yarn over, then insert the next stitch. Now yarn over and bring the working yarn through the stitch hole, which we just insert.
  Now we have 3 loops on the hook. We yarn over again, then bring yarn through all 3 loops tog. The half-double crochet is finished.
Do it again. It's called half-double crochet.

Video

At first, make a yarn over.

Then insert into the next stitch.

Yarn over and bring the yarn through the stitch hole.

We yarn over again and bring yarn through all 3 loops tog.

The half-double crochet is finished.