I am trying to install a low voltage lighting system. I already have an older 200 watt transformer. It has 4 terminals (2 Load, 2 COM), and a High/Lo switch. I can't find any manual or instructions on how to connect this, because all the new transformers only have three terminals. How do I connect my wire to this? Do I need to use all 4 terminals? What is the High/Lo switch for? Am I supposed to run one wire from two of the terminals, and come back and connect the other end of the wire to the other terminals?