I had to do some modifications to make this weave work with my rings. I am very happy with the results. You can also find the copper and black bracelet in a kit.

Buy the kit!

Start with 2 6mm rings and connect them with one 4mm ring.

Place a 6mm ring over the 4mm ring, as shown.

Now add two 4mm rings passing through the top 6mm ring and each of the outside 6mm rings as shown.

Add two 4mm rings to the bottom half as  you did for the top.

This next ring is optional, but I think it helps keep the weave uniform. Add one 4mm ring to each set of 4mm rings on the top and bottom. 

Repeat to continue. Use the outside ring in the previous knot as the first outside ring in the next knot.

Celtic Daisy

I also figured out that you can make a Celtic daisy. Make a chain of 6 Celtic knots, leaving off the bottom black 4mm rings.  Attach the ends together. Then run a black 6mm ring through all of the bottom copper 4mm rings to form a circle, and you have made a daisy. It's a little challenging to get all of the copper rings on the 6mm black ring. So, I added 8 of the copper rings, closed the 6mm black ring and attached the remaining copper rings.