Help an Old Man Please - RAX120 — Nighthawk AX12 12-Stream WiFi Router

With this router, how do I set up a mesh network with it? Can I just buy some of these? 

Nighthawk® Mesh WiFi 6 System Add-on Satellite Model: MS60

Will those play nice with that router? Also, I have 2.2 acres of property that I need to cover with this network. Can I use some outdoor housing box to keep the mesh satelites out of the weather? Or are there any wifi-6 802.11ax outdoor mesh units that you can suggest?

If I am going at this in the wrong way, please help me out and point me in the right direction to the solution that makes the most sense. The home is only 960 sq ft. So thats not any issue. It's located in the middle of the property. But I have gardens and orchards around the perimeter that I wish to implement a more intelligent irrigation system. And I have driveway gates, and a parcel box, as well as a need for video.

I am so thankful right now for the person who responds to this for me.

Much Thanks In Advance