Nighthawk MK63 AX1800 multiple networks

I currently have a cable modem/router and I'm considering buying a Nighthawk MK63 AX1800 to create a secondary network that is sperate from the primary network that the cable modem provides.  The secondary network will feed from the primary network, but isolated.  Does anyone have any good info doing that?

                      |-Device1

CableModem-|-Device2

                      |-others

                      |

                      |-NightHawk Secondary network-|-Doorbell

                                                                          |-Camera

                                                                          |-Laptop

                                                                          |-others

What I want is something similar to this

Thanks in advance.