Any way to repurpose Airtel v fiber router as extender for airtel xstream?

Hi. I'm basically looking for information on how to accomplish the title. I have an old Airtel V Fiber router lying around and want to connect it to my airtel xstream ONT to be used as a repeater. Does anyone know what configuration changes I should make in both the routers?

Try plugging a ethernet cable from ont lan port to lan port of VFiber router. That could work.