We use linksys for our router. You can access the the routing box by typing the address for the router box and clicking go. Then you have the option to set up a code to protect your network. Also, change the password to access your router box. I know that linksys comes with a generic password. We had a neighbor that kept accessing our router box and changing the name of our netework. You can also change the name of your wireless network so that you will easily recognize it.
Then on your laptop you can view available networks, choose your network and then type in your code to connect.
Some cable or dsl modems work as router boxes. That means if you have a router box and a cable or dsl modem that also has a built-in router box, you need to access the cable/dsl modem and change the setting so that it will not use it's built-in router.
Another option is to just run a cord from your router box to your laptop. My laptop is in our living room and my router is upstairs in a bedroom. Since I always use my laptop while I am sitting on our living room couch, DH ran a cord down the wall, so now my laptop is wired.