Connecting used router to century link

> Model: R7500|Nighthawk X4 AC2350 Smart WiFi Router

   Is that accurate?  R7500 or R7500v2?  Look for "Model" on the product
label.  Firmware version?  Connected to what?

> Just purchased used R7500 router. [...]

   And did what with it?  Which type of CenturyLink service?  Is there a
modem involved?

> When installing tells me [...]

   "installing"?  What, exactly, are you doing?  "tells me"?  What,
exactly, "tells" you what, exactly, when you do what, exactly?

> [...] connect to my new routers address. [...]

   What, exactly, does "my new router[']s address" mean to you?

> [...] Any suggestions?

      https://en.wikipedia.org/wiki/RTFM

   Visit http://netgear.com/support , put in your (actual) model number,
and look for Documentation.  Get the User Manual.  Read.

   When dealing with a used device, a settings reset is usually a good
way to begin.  Look in the User Manual for "Factory Settings".