First of all you need to work around the stitch that you have made in the previous row. To make this front post double crochet you have to first loop over the yarn on the hook. Now pass this into the first stitch of the previous row at the bottom. Go around the stitch to the back and from there you have to come back again to the front. Now yarn over and pull it through the loop. Again yarn over and pull it through the two loops as shown. Again yarn over and pull it through the last two loops of the stitch. That's it.