New house with centrally located Arris modem/router furnished by ISP. Ethernet connections built in while house under construction go to several rooms and connect three computers, three smart TVs. I also added Powerline Adapters to run such things as printers and Cloud storage devices. Finally, I have several devices such as phones and tablets connected wirelessly. I have no idea what I'm doing and as a result some devices don't show up on the network even though they do connect to the internet and I can't backup things from one computer to another. Should I try to undo everything and start over or is that even possible? Is there a step by step set of instructions for how to either correct the mess I have or start over? Sorry for the long, rambling description of my problem. Any help would be greatly appreciated.