Incorrect Update Instructions Nighthawlk

> [...] An email received [...]

   Not by me.  With my weak psychic powers, I can't read your e-mail.

> [...] They log into the router using web address routerlogin.net or
> routerlogin.com, [...]

   That doesn't always work, as explained in the above-cited thread
(along with alternatives):

>       https://community.netgear.com/t5/x/x/m-p/1976674

> [...] The product label also shows a password, [...]

   Again, I can't see at what you're looking.

   I'd expect the product label to show two (different) types of "a
password", as explained in the User Manual, under "Types of Logins", as
suggested above.

> [...] it shows an error screen saying the connection must be by WiFi,
> despite the instruction article saying to use a cable. [...]

   Which is why it has been described (in the above-cited thread) as
"what may be the worst error message in the world".

   Yes, some Netgear documentation stinks.  You could pout or complain
about this.  Or, you could find and read additional information which
should let you get on with the task at hand.