Question: How do you attach the wall plate to the wall?

Answer: You will need to attach them to a gang box or wall bracket. None are provided. You can acquire these at a local hardware store.

Question: Can the metal plugs be removed from the plastic plate? Answer: Yes, they can. Question: How do they cables in the wall connect onto the backside of the plate?

Answer: The connectors are coupler type, meaning there is a jack for plugging in terminated cables on the backside as well as the front.

Question: What is the difference between the decora style plates and the non-decora plates?

Answer: The difference is mostly aesthetics. The Decora style plates have an inner plate which attach directly to the gang box and a finishing plate that surrounds and frames the edges. The other type of plate has an under plate that attaches to the box and a cover plate that covers the entire under plate less the cut outs for the connectors. The non-decora style plates protrudes from the wall more than the decora style do. The choice is ultimately a matter of personal preferance.