Then just choose any random tutorial. As I said before, the only difference between all the seperate tutorials for all the different routers is where to go in your router control panel to find the port forwarding page. If you took just one minute to simply look around the control panel, you'd find it no problem.
As for username/password, go
here try some of Linksys' other default username/passwords. If none of those work, ask your parents if they changed it.