Step 4: Final layers
The two side pairs are going to be installed the same way as the middle pair was. But now you connect them to the C shaped connections closest to them. One to the outer, and the other to the inner of their side.
Then you install the next lower middle pair of two in the same fashion of opposite alignment, and connect them to the two middle C connections. However, I wouldn't advise you to connect the bottom most LED into it's set yet, as you are about to bend a lead under that connection.
The next two I installed aligned in the same direction on opposite sides of the bottom middle LED. I bent the + lead of the right one between the bottom center LED and it's mate. Connecting to the - lead of the bottom left LED, and the outer left C shape. You then take the bottom left LED's + lead, and bend it to the bottom right LED's - lead, and then to the opposite outer C shape.
The final LED I bent the + lead to the bottom middle's + lead, and the - lead over to the outer left C shape. You should now clip any stray leads, and make sure there aren't any shorts.
You will end up with the pairs covering all but 3 of the possible combinations that 6 solid connections will give you. So poke around with a 3v + and - wire and watch the different LEDs light up one by one.