Setup WiFi Extender AC1200 EX6110

> [...] My model is not on the list, [...]

   Try the appropriate forum?:

      https://community.netgear.com/t5/x/bd-p/home-wifi-range-extenders

> [...] And why does it ask for model number in the Subject box, and
> again in the next box?

   The Subject is visible to other participants in topic lists.  The
other (with more details) appears in the posting itself.

> [...] What does it mean by Location? Country, city, address, room in
> the house??

   Which do you think would be most useful?

> [...] When I enter the recommended webpage (not allowed to put it
> here) in the brower (several different browsers actually) I just get a
> general page saying 'You are not connected to your extender's wifi
> network'. How do I get the installation page? [...]

   Welcome to what may be the worst error message in the world.  For an
explanation, try (router edition):

      https://community.netgear.com/t5/x/x/m-p/1365830

   Briefly, the idea is that "[www.]routerlogin.net" (or ".com") should
point to your own router, but that's true only if you use your own
router for DNS name resolution.  (Or, if the Netgear router can
intercept your DNS queries.)  Regardless, you should be able to get to
the thing using its IP address, if you can determine (or guess) that.
Normally, that would be something like "192.168.1.1" (for a plain
router) or "192.168.0.1" (for a modem+router), but it could be
different.  ("10.0.0.1" is a typical alternate, for example.)

   For an extender ("mywifiext" instead of "routerlogin"), which
normally gets its IP address from (the DHCP server in) your main router,
you might need to ask that main router which addresses it has granted to
its client devices.  On a Netgear router, that would typically be in an
"Attached Devices" report.  (See the router documentation.)

   If the extender is not connected to a router (DHCP server), then its
default IP address should be "192.168.1.250".

   Visit http://netgear.com/support , put in your model number, and look
for Documentation.  Get the User Manual.  Read.  Look for "Find
Extender's IP Address" or "Cannot Access mywifiXext.net" (remove the
"X").

> [...] Any suggestions?

   Here's a radical concept which works for some people:

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

> [...] (not allowed to put it here) [...]

   I'm not sure exactly from what this prohibition is supposed to save
us.  Nor what makes it a bigger problem than the "routerlogin" names
which _are_ permitted.  Another Netgear mystery.