Hello @Anita
If you have an existing Google WiFi or Nest WiFi Router already set up as your original router, then you can add a Nest WiFi Point unit to that system to expand the coverage area. However, it cannot be added to a non-Google/Nest WiFi system – it's not a WiFi extender.
If you do add a Nest WiFi Point to an existing Google/Nest WiFi system, placement is important. If you put it in an area that has poor coverage now, it won't help much if at all, because it has to get a WiFi connection itself. Instead, it has to be placed close enough to the primary Google/Nest WiFi unit to get a strong 5GHz connection for itself (typically one or two rooms away). From there, it will provide 2.4GHz and 5GHz coverage to more distant clients (which may be in that "dead spot").
