Hi I have just bought the Deco m4 and I am a bit unsure if I have set it up the best way possible. 

I installed it using the default as a router. That seemed fine except the new deco WiFi was visible and my old 2.4 and 5 ghz networks were also available to connect to. 

I could connect to any which didn't seem a problem except my son's xbox would not work on the deco WiFi, which is what I wanted, as the slave is in his room. 

I was getting a double nat error, whatever that is. I wasn't sure if it was because there were multiple wifi networks on the one line. 

I could only get it working by changing the set up to an access point. 

I don't really know what the difference is or the pros and cons of either? 

I can still connect to any of three wifi networks, the deco one and the two different router frequency ones. 

To have it in router mode, do I need to turn off the wifi on the original router or something?