help with reversible log cabin afghan

Hi, I am new to this forum, have been crocheting for about three years... but I am stumped by this pattern on Yarn Council website! I understand basic crochet terms, but some of the terms in the pattern baffle me and I hope someone can help, is there someone who has successfully made this pattern?
My problem starts at the end of Row 2, "... 3 dc in top of next ch-4." I don't understand this, as there is a ch-3 at beginning and at end of Row 1, but no ch-4 ... however, if I make the 3 dc in top of beginning ch-3, it seems to work. So, maybe not so serious. But Row 3 is really a problem for me.
Row 3 says: "Attach CB to ch-3 ring at the end of Row 1, ch 3; drop lp from hook, insert hook in top of last dc of corresponding row in previous color and draw dropped lp through -- beg-of-row joining made, 6 dc in same ring; sl st in top of ch-3 of corresponding row in previous color -- end-of-row joining made: Ch 3, turn." I wonder if someone could walk me through the beginning-of-row joining: if I don't turn after Row 2 and attach CB to ch-3 ring at end of Row 1, then draw ch-3 loop through first dc of Row 2, do the 6dc go into original ch-4 ring? I have tried many times to work this out. The remaining rows look easy enough, although I'm not sure about those hanging loops yet ... would help if I could find a video or someone could just walk me through this. The pattern looks lovely and I finally have the quantity and colour of yarns, would really appreciate help!