1. No: this is referring to the short wires already on the adapter, and those wires should go to OpenGarage.
2. The long wires are referring to the white wires in the OpenGarage package: on one end, screw the two wires to the adapter’s big metal screws, the other end goes to your garage system’s door button holes.
Basically, imagine you how you would install the door button (which is what the adapter is made of) to your garage system. The only addition here is the two short wires on the adapter go to OpenGarage.