Derek wrote:

I have an AT&T FIOS Phone/WiFi router that stinks.

I have a faster WiFi router I want to use to replace the AT&T for the wifi and router parts.

How do I do this ?

Basics I think are to:
somehow keep the AT&T unit so phone will work but not use it as a router or a WiFi.

connect new wifi router to AT&T with a cable.

I can get into the AT&T unit and print the settings but I do not know what settings are
important.

What things do I need to do to make it all play and not have to change all the passwords
on my equipment.

Please give me steps in order with as much detail possible

Thank you so much.

ATT does not allow non ATT equipment on FIOS/UVerse/VDSL lines.
They do allow non ATT on analog or regular DSL.
You will need to rent a better modem from ATT.
That is what they have told me repeately for the last 2 years.