Step 1: If you haven't already done this.
Before you can connect to the wireless router you will need to configure the wireless router to work with your ISP (BT broadband) and appropriate settings for your laptop.
To do this you will need to plug a computer into the wireless router using an Ethernet Cable and use the CD provided. You may need to contact BT for the Internet settings and for further assistance.
Netgeat Quick Start Guide:
You should be able to find a manual or a link to more resources relating to you router on the CD.
Step 2: Once your wireless router is set-up you will need to connect the laptop to your wireless router.
If you are using Windows7 or Windows Vista you should see a little wireless icon on the bottom right of your start bar. Click this and then on the name of your router.
This links explains the process in more detail: http://windows.microsoft.com/en-US/windows7/View-and-connect-to-available-wireless-networks