When you buy your router (the shop you get your laptop from may be able to help you choose one - if not just pop into PC World and ask them for advice) it will come with a setup disc that you will put in your main PC.
This will then guide you through the setup process (which cables to unplug and when, where to plug them, when to switch on your router etc - it really is very simple to follow)
It will then configure your PC and the router and will let you know when everything is finished. It should then be a simple case of switching on your laptop and searching for your wireless connection (network). Once you have found it, and connected to it, tick the box that says you want to always use this network if it is found and then you shouldn't have to go searching for it again.
The best thing to do when you initially search for your network is to sit next to the router, where the strength will be strongest, then move to where you want to use your laptop. It should be OK provided your walls aren't 12 foot thick, or your favourite location isn't half a mile away.