ARRIS Surboard>Reonlink Home Hub Pro>TP-Link wifi Extender

I upgraded to the Reolink Homehub Pro from my Blink and I'm not happy with the installation process. I also purchased the Reolink Elite (panoramic) for the front yard. I've never had connectivity issues with my Blink, but with the Reolink, it's not connecting, or when it does, it constantly disconnects. So I purchased the TP Link wifi extender. Do I connect the extender to my ARRIS or my Homehub Pro? What is the best way to utilize the extender?

I'm at my wits end and need advise. Thank you!