Adding a Verizon router to existing Fios network

[#1]

I recently re-signed up for Fios service after a brief period without service.  I purchased my previous router from Verizon, rather than rent it when I had service until April '20.  I purchased the new modem/router when I signed up again in July. I would like to be able to add the router I previously purchased (Fios-G1100) or the access point (Actiontec WCB6200Q) to the network that was recently setup - in order to boost the signal strength on middle floor - I have 3 floors - the main router in the basement and the access point in the 3rd floor office.  Is this something that I can do? I have an ethernet port and fios cable box in this floor, so I have coax already run here.

Thanks!

[#2]

You should be able to add it - as long as the new one is still the G1100. I believe you can still do if you got the new G3100 instead, but that part i am not sure.