I'm sure we can work it out between us
It's at my mum's, but I can remote in at some point (when she's awake!) and have a look if necessary.
As far as I remember, I plugged the extender in to the mains and the network lead from the extender to the laptop (or desktop, whichever - it's only for initial setup, it doesn't have to be permanently connected).
Once it's connected, the computer should "see" the extender through the network lead.
If your extender's IP address is the same as my mum's, you should be able to type it in to the address bar at the very top in your browser (Internet Explorer or Chrome or whatever) NOT in to a Google search etc (common mistake - sorry, I don't mean to be condescending or anything, I don't know what your "level" is!)
The IP address of my mum's extender was
http://192.168.10.253
If that doesn't work, it might be that yours is different?
You can find out what yours is by opening a DOS prompt (click start / (you may or may not have to click run as well) / type cmd / press enter). I think you can find the command prompt under start / accessories as well - depends on what version of Windows you're running. This should open up a DOS / Command prompt (black and white text only window). You type:
ipconfig /all
(followed by the enter or return key - there's only one space in that command and it's after ipconfig and before the forward slash - the slash on the right, not on the left)
It should tell you a bunch of possibly confusing info, but the IP address of your "Default Gateway" (probably 192.168.xx.xx) should be in there somewhere. You can make the DOS / command prompt window bigger, or scroll it up, if necessary.
You'd type that 192... address in to your browser's address bar, which should bring up the "web page" (actually it's a settings page held on your extender rather than a real web page).
If it brings up your Sky (etc) router's settings page, it might be best to turn off your wireless (usually a switch on a laptop, flight mode etc) so that it doesn't get confused - while setting up the extender, we want it talking down the lead to the extender, not over wifi to your existing router).
You should be able to configure the extender from there, I think you have to select your main wireless router provided by your Internet Service Provider (ISP) - usually called Sky????? or BT????? or Virgin????? -something unless you've changed the name of your wireless network.
Once that's done, you don't need the network lead and you can unplug the extender from the mains and put it anywhere in the house in order to extend the signal (half way between your Sky (etc) router and your PC would seem logical, but it depends on the structure, walls etc of the building as to how strong the signal is at different points in the house - obviously you'll need a mains socket but other than that you can try different positions or see how many wifi bars your smartphone etc has without the extender in different areas of the house). Unobstructed wifi signals go around in a circle with the router at the centre, then downwards, so you might find it works better from an elevated position. You might have a specific spot for the extender because you want to connect it via the wire to something else in the house (e.g. a Smart TV that doesn't have wireless).
Hope that helps, let me know if not. It all came out as a flurry of thoughts rather than organised in numbered steps I'm afraid. Bed time in a bit! Private Message is best (as you've just seen!) as obviously I missed the replies before.
And if there's anyone out there who finds this useful and has an IT tech job for me in Stourport or Brighton for when I'm made redundant in September, I'm all ears!