[Equip] RT-N66U router and verizon wireless network extender

Let me preface by saying I am NOT tech savvy. I have a RT-N66U router and I am trying to setup a verizon network extender that I recently purchased. It is connected to the router via a CAT5 cable. The SYS light is red, keeps blinking rapidly and the GPS light is solid red. I have been reading on the internet and cannot figure out how to fix this. I tried chatting with ASUS, the guy asks for my WAN IP ( 10.0.0.15) and says I have to contact my ISP b/c I need a public IP? I would appreciate any and all help. Step by step directions would really help. Thank you!