Router network security pass phrase WPA-PSK wireless Key !

[#1]

When I joined plusnet I struggled setting up my router mainly because of the numerous names for the same thing.  The leaflet included with the router " Setting up your Thompson Gateway" refers to, The "network security key (or pass phrase)" and the  "WPA-PSK key". The included sticker refers to the "wireless key".  This https://portal.plus.net/support/broadband/hardware/thomson_changepass.shtml ; refers to a "password" which I am assuming is the same thing!.  Is it?.
Please choose one name and stick to it.

[#2]

That article refers to router models no longer provided (the current one is the TG582n) but the password referred to in the article is NOT the wireless key mentioned in the other references.
The password mentioned in the article is that for accessing the router settings themselves; various username and password combinations were used on the older models but for the TG582n this username is admin and the password defaults to the serial number of the router (starting CP...). The wireless network has an SSID which will be PlusnetWirelessXXXXXX and a key; these are now given on a plastic card and printed on the base of the router (and in the GUI pages).
In my opinion having these details written on a card should make things clearer, but based on forum posts some users still find having several usernames and passwords confusing.

[#3]

I have a Thomson 585v7 router. Please tell me via a link how to change the password/key. The current password/key is written underneath the router following WPA PSK. 

[#4]

The Disabling Wireless on the Thomson TG585v7 Router Customer Support Library article explains how to get to the router GUI configuration page dealing with wireless settings. The wireless key is one of these settings and the one you see should match that written underneath the router.
Change that as desired (rather than disabling wireless which the article covers) and click Apply.

[#5]

Done thanks to this
First, we log into the router using an administrator level account and select "Home Network" from the left hand side
Now click on the link under Wirless, next to the Pylon type thing.
You are now on the screen with the evasive "configure" link in the top right corner tucked between Details and Help, click this and your where you want to be.

You can now see your network key as printed on your router. Delete it and insert your chosen key (write it down!) then click apply. You will then be disconnected from the internet. Search for available wireless networks. Click on yours and use the new password.