Open your browser and type 192.168.1.1 in the address text box. This should access your Linksys router.
The default user name should be blank or admin.
The default password should be admin.
Once you are able to access your router, navigate to the SSID entry.
If you are using default user name and password for your router, it would be a good idea to change them to help secure your router from outsiders. Be sure to write them down and store in a safe place because, trust me, you will not remember them 8 months down the road. It's not a good idea to use your real name for anything.