how to turn wifi off with pace 5268ac router

You need to place the gateway in bridge or pass through mode and allow the Netgear to handle all of the router duties including WiFi.

If you turn the AT&T Wi-Fi off, then it will not work, and you'll be relying on the Netgear Wi-Fi.  Is there something wrong with the Netgear Wi-Fi?

If you're configuring the Netgear as a router (default), then you'll want to set up DMZplus on the 5268AC and point it at the Netgear.

If you're configuring the Netgear as an access point, then you don't need DMZplus on the 5268AC, but some Netgear features won't work.

OttoPylot

You need to place the gateway in bridge or pass through mode and allow the Netgear to handle all of the router duties including WiFi.

Some AT&T gateways don't support bridge mode so you need to use pass through instead. This effectively disables, at least in theory, the router/WiFi functions of the gateway so that your Netgear takes on those functions. The modem half of the gateway is not affected so that authentication etc to AT&T remains intact. I am not familiar with the Pace gateway so hopefully @JefferMC will have better advice.

As far as your Ring Doorbell, or any other 2.4GHz device, a lot of folks will use the Guest Network, which is always 2.4GHz and point their 2.4GHz devices to that. To make it a bit more stable, assign a different SSID and password to the Guest Network and point your devices to that.

None of the AT&T Gateways have an actual bridge mode.  They have either IP Passthrough (BGW210, BGW320) or DMZplus (5268AC), which are pretty much exactly the same except for name.  What they do is a lot like bridge mode, but it has some differences, including the fact that the Wi-Fi can still work.

@OttoPylot 

Use of a personal router to carry WiFi traffic does not require the Att gateway to use DMZ or IP passthrough. 

@wmh9680 

Turning off WiFi on the gateway is exactly what you want.  Let the Netgear device do the work.  I'm not sure which instructions you're following, but easiest path is to set your new device in Access Point mode.   Good luck.

Well, I was on the phone with ATT for about 2 hours yesterday since I could not use my att wifi on my laptop (the green wifi light on the gateway has not been on since I made some changes at the gateway online site, 192.168.1.254). They tried everything and finaly after 2 hrs they got everything reset and the wifi works. The guy was VERY patient and did get it resolved (I have a firstnet account since I am a ff/pm so I called their customer service) but between his accent (imagine that) and my hearing aids quit connecting to my cell half was thru it was a very trying experience for both of us. He did tell me that I do not need to disable the wifi on the gateway as it will disable itself when I connect the orbi pro netgear router. So the att wifi is upand running but I still half to try and install the netgear orbi pro. What do you think about what he said about the att gateway wifi shutting itself off? That is the opposite of everything else I've been told. Although the wifi is working now my experience it it is only temporay until it acts up again. He said he might send me a new router and I told him I've been told that before (they were sending me a new one that would work better and be much faster) last time thay said that and they sent the exact same one out, that's why I thought I would try the netgear orbi pro. I'm not the smartest guy on the block but I have built alot of computers from scratch an always do all my own upgrades my self inclucing Linux and Raspberry Pi but I'm stumped hear, Thanks, Mike

as it will disable itself when I connect the orbi pro netgear router

This is untrue.

What do you think about what he said about the att gateway wifi shutting itself off?

That he doesn't know what he's talking about.

Get your new router up and once it's working to your satisfaction, then you can turn off the Gateway Wi-Fi.  Manually, because it won't turn itself off.

If you have an Orbi, a good solution, why do you need or care about the WiFi in the gateway?  Getting that (personal router) setup working is about as easy as it gets.  If something is unclear, perhaps asking a more pointed question can be answered.  

I love my Orbi! Very reliable and stable.