This is the breaker I installed in our rig. I only replaced the breaker that goes to the hydraulic pump, left the other one alone. If, like on our rig, there are two cables leaving the load side of the old breaker, just install the cables the same way. The second cable is the one that feeds 12 volts to your main panel. You may have to enlarge the holes in the ring connectors because the posts on the new breaker are a bit larger in diameter than on the old breaker. I also show a photo of where our breaker is located.
https://www.amazon.com/Bussmann-BP-C...t-video&sr=8-1