You need to understand how different stringing configurations impact the voltage current and power of a solar array.
How to wire 3 solar panels together.
The positive wires are connected to a positive connector within a combiner box and the negative wires are connected to the negative connector.
If you look at the arrows along the white and red lines they are showing the direction of flow.
To solve this problem and to optimize the energy performance of the entire system it is advisable to wire two panels in series obtaining a doubling of the voltage and then wire in parallel the three pairs previously wired in series so as to have doubled the voltage and tripled the current.
The white line is the negative connection all 3 panel negative wires are just simply tied together and to the wire that runs back to the negative connection on the charge controller.
The red line is the positive connection to the panels.