Crocheting around the posts is an interesting way of adding texture to your crochet work. You can either crochet from front to back which is called a front post stitch or from back to front called the back post stitch. I have used standard American terms in my tutorial. I will show you how to make a front post double crochet (fpdc)
As shown below the vertical part of a stitch is called the post. I have worked a few stitches using the regular double crochet (dc). My next stitch is going to be front post double crochet (fpdc).
Wind the yarn over the hook as you do for the regular dc but instead of inserting the hook into the top of the stitch insert it from front to back into the space between the posts (the post where you worked your last stitch and the post in which you have to work your fpdc), take it behind the post and bring it again to the front as shown below.
Wind yarn over the hook and pull the hook out.
Now finish it as your regular dc.
For working the back post double crochet (bpdc) you have to insert your hook from back to front.
take the hook around the post and exit though the next space
wind yarn over the hook and pull the hook out.
Then finish your stitch as a regular dc.
Below you can see 3 bpdc stitches worked one after another.
Have a great day!