Ravelry: Flat Braid 3-Ch Crochet Join Tutorial pattern by Margaret MacInnis. Long, photo heavy tutorial that is VERY GOOD. If you struggle with this method of joining or want to learn, then read/use this tutorial.
Simulated braid join This method simulates a braid join and is accomplished by crocheting pre-edged blocks together. It's fast and easy but uses more yarn and creates a ridge on the back between squares.