We order the Verizon FIOS router for every install yet seldom use it. Still, it must be kept on site for testing when Verizon demands it.
Verizon wants to test to their router and thus want to see this architecture before they test : Verizon FIOS fiber --> Verizon ONT at customer premise -->Verizon FIOS router-->Your LAN switch
Many IT professionals create this architecture: Verizon FIOS fiber --> Verizon ONT at customer premise -->IT vendor supplied router-->Your LAN switch
Thus, for testing, you need to know how to move the FIOS Ethernet cable coming from the FIOS ONT.
Remove the cable from the your router WAN port and move it to the Verizon provided router WAN port.