Did you figure it out? It's such a pretty afghan!
I just wanted to make sure you started off making the ring before starting round one. "With A, ch 4, sl st in beg ch to form a ring."
After doing the slip stitch in the beginning chain, you have a circle. When you chain 3, it extends up from the circle and counts as a dc for the first set of 3 dcs. If you look at the picture, you see the ring in the center, then 4 clusters of 3 dc around it with a ch2 between each cluster. When you have completed the 4 clusters/ch2 in the ring, you'll be back to the first ch 3 (which was counted as a dc for the first cluster). Slip stitch into the top of it--that would be the 3rd (top) chain of the ch3. You now have a closed circle of 4 clusters, each separated by a ch 2 space. You will continue closing each round before beginning a new round.
Here's a good video that shows slip stitching into the first ch3: http://youtube.com/watch?v=MwD5tSyyoyE&feature=related
This one is good for making a granny square in general, although she does the last sl to the ch 3 a little differently: http://youtube.com/watch?v=gJCd_-V2D5k&feature=related