24v starter

Hi Everyone, Could someone explain to me how exactly the 12/24V relay works based on the FSM wiring diagram. As far as I can tell from the diagram: 1. + from the LH battery connects to the first (left hand) terminal on the 12/24 switchover relay and directly to terminal C on the starter 2. -...

The starter was in working order but rough cosmetically and around the edges when I removed it. Had it rebuilt by local master at his trade. Told him to go through and replace/rebuild anything that showed any sort of wear or would wear out in the years to come. Brand New: OEM field casing/yoke...