NETGEAR Nighthawk R7000 WiFi Router - LAN gone

> NETGEAR Nighthawk R7000 WiFi Router [...]

   Firmware version?  Connected to what?

> I wanted to set up my router for a Mixing board. [...]

   Not a very detailed desription of that device.

   Why would you not want to set up your (unspecified) "a Mixing board"
to work with the router (with its default settings)?  How much extra
work are you trying to make for yourself?  If you have some actual
reason, please reveal it.

> [...] I went to the settings on browser and updated the Mixer for the
> LAN IP address 10.10.2.1

   _Whose_ "the settings"?  The settings of your (unspecified) "the
Mixer"?

   Why the odd-ball IP address(es)?  You can pick any "10.a.b.*" range
you want, but why not the defaults?

   How did you choose that address?  What's the LAN IP address of the
R7000?  I'd expect the router to be at ".1", which would make that a
very bad choice for any client device.

> The video I watched [...]

   Thanks for not including a link.  I hate watching low-quality
"instructional" movies.  On the other hand, with my weak psychic powers,
I can't see what you watched.

> [...] change the DHCP starting IP address to a number similar to
> 10.10.2.5 to avoid conflicts.... anyway I did that. [...]

   If _you_ are handing out (static) addresses (like ".2", ".3", and so
on) to some of your client devices, then you should not leave those
addresses in your router's DHCP pool, so that it will think that it can
also hand out those same addresses to (other) DHCP client devices.

> [...] The thing is there are only 4 LAN slots so maybe this is the
> problem.....

   No.  There's no required correlation between the number printed near
any of those connectors and the IP address of any connected device.
(Especially not for "1", which you probably shouldn't be using as an
address.)

> When rebooting the router there is now NO LAN settings. [...]

   I don't know what that means.  As usual, showing actual actions
(commands) with their actual results (error messages, LED indicators,
...) can be more helpful than vague descriptions or interpretations.

> [...] I tried factory reset (I think that only resets the PW). [...]

   Think again.  Visit http://netgear.com/support , put in your model
number, and look for Documentation.  Get the User Manual.  Read.  Look
for "Factory Settings".  Further reading might not hurt, either.

   In the words of the philosopher Williams, "If you don't think too
good, don't think too much."

> [...] No idea what to do now.

   Start again, and reconfigure your router.  You might want to reset
the network parameters of your (unspecified) "a Mixing board", too,
before connecting it to your router.