|Have tried to use one of these two possibles?|
192.168.1.1 and 192.168.0.1
This is from the support site:
Lots of useful help (setup etc.) there.
If neither of the above addresses work... power cycle the router. (Switch it off, wait about 30seconds or so then power up again). Then try the addresses again. If still "no joy" (old RAF slang for it's working OK) then use the reset routine.. There will be small hole in the rear into which you insert a large paper click and press on a wee small contact/button for a few seconds. The router will recycle/reset itself to factory defaults.
The reset will disable wifi by default; so all connections must be via cat-5/ethernet cable until you re-enable wifi...
Then try the addresses again as above.
Once you can get into its homepage/seetup you will need to re-enable wifi and that is when you can set up some security.
Note carefully the router's SSID (the name it broadcasts to world as wifi); write it dwon (if it it's not already on the base of the router. Go into wifi set and note the default password/access-keyt ; again it may also be on the base of the router.
Then look for the option to set up mac filtering. This is an option to create a list of wifi devices - their mac addresses. The list can be sued to allow wifi access "only" to those on that list (clearly not your neighbours etc.); or to disallow those on that list... the default setting is there is no list established; thus anyone who knows the wifi access-key/password can use your wifi...
You can also change the SSID - but if you do "write it down and also email it to yourself and save the info n the saved messages folder of your email account. It's a bit like a free cloud storage system. Do the same with the wifi access-key - ideally change that too and again note carefully what you create and save it etc as with the SSID.