Good Day everyone

I have inhereted a system that has a Sunsynk 8kw and 1 Sunsynk 5.12kwh battery. The client would like to ad another battery. My question is how is this doen can you just ad another battery with the communication cables and dipswitches then it will see the 2 or are there settings that have to be doen? What are the pinouts of the communication cables? I have never used the sunsynk batteries before. Any help would be apprecated.