No you have not :) just solder the red wire to the last battery on the other side (the one without any bar or wire connected to it. the other side of battery should be connected by bar to the next one. The pack always ges : - to + to - to + etc where the first - and last + go to wire
Radek
V4 D8 - RX8, XERUN 4168SD
F1-09 - Tekin RS Pro, 17.5t Redline, 2S LiPo
Sakura Zero S - LRP, Saturn 20T, 2S LiPo
*EX-10 Eurus*