The photo above illustrates what the pattern instruction phrase join to form a ring means. It is done by making a slip stitch in the chain furthest away from the hook (in this case, it is the sixth chain away from the hook).
Many patterns which are made in rounds begin with a chain, which is joined by slip stitch to form a ring.
How To Slip Stitch: Insert the crochet hook in the stitch to be worked, wrap the yarn over the hook, pull the yarn through both the stitch to be worked and the loop already on the hook, all at the same time.
For my basic triangle pattern, this is the first step in making the crocheted triangle shape, which is illustrated more in the following photos of this step by step tutorial.
Next Step of the triangle shape --->
Crochet photo copyright 2008 by Sandi Marshall, licensed to About.com, Inc. Per copyright law, do not use my pattern photo on another web site, blog page or elsewhere. Instead, you may give out the URL of this photo page, for others to come here for themselves. It makes a world of difference to me, in helping to enable me to continue designing new patterns and new crochet tutorials. Thank you.