netgear ac1200 not connecting to comcast

AC1200 is a speed and not a model. 
And then your signature you put the A6150 which is a usb adapter which you wouldn't setup with your phone. 

So what device do you actually have? 

There's a support site with access to manuals, firmware, install guides, etc.
Go to https://www.netgear.com/support/
Type in your model number and from there it'll take you to the above.
Its a great resource to start with. You don't need the phone to install the routers.