I am building the brain game. Now I am trying to solder the battery holder onto the board. I see that there are 2 places on the battery holder to solder the jumper wire up to (one is next to a positive side of the battery and the other is next to the negative side of the battery). I also see that the board has a positive and a negative pad to solder the jumper cable onto. What I am wondering is which side of the battery holder should the positive pad be soldered to and which side of the battery holder should the negative pad be soldered to?