Which router and extender to use with ATT fiber? (newbie post)

I've been searching forum posts, and it looks like a lot of extremely tech-savvy people here. I definitely lack in those skills, so please bear with me .... 

We are having ATT fiber installed next week. I have also ordered ATT's Wifi Gateway to go along with it. Our house is a two-story box, and we would like to have the Wifi reach both floors as well as two separate outdoor spaces (where we plan to have pods of children for remote learning throughout the schoolyear). There isn't a lot of square footage involved, but we would need to have a strong signal available everywhere so that the kids can stay reliably connected, and so that the adults can also work. 

It's my understanding that we will need 1) a wireless router (like ATT's Wifi Gateway that's being delivered along with the fiber service), as well as 2) one or more extenders. 

Should we stick with the ATT product for the wireless router? Or should we replace it with another product? And which extender has worked well with this service? 

I would need everything to be basically plug-and-play since I have only a basic skill level. 

THANK YOU so much for any advice!