Balance cable for LiPo batteries
If you haven't figured this out yet, series charging is accomplished by putting all the main power leads in series, and then putting the balance leads in series as well.  The challenge is that each balance lead has an extra pin from the number of cells -- that's where the confusion comes in.

The first and last pins of the balance leads are directly connected to the first and last cells respectively, positive and ground.  Think logically about how a fully-series pack is constructed, and where the balance taps are.  They are between the positive and negative of each cell in series.  Since your balance leads are broken out, you have one wire for a positive, and another wire for a negative.  

Connect them together, and take the tap as one of the balance wires.