MAC Can't connect properly to my school's internet?

Hello, I am having trouble connecting to my school's internet. I enter the netword name and password properly and airport says that I AM connected to the internet. I believe there is supposed to be some kind of authentication for my school username and password when I go into the web browser but it never comes up. Is there a way for me to reset my internet so that it connects to things properly? I think I may have changed a setting or something that is making it not pick up properly. It does say that I am connected and I have turned off all of my firewalls and adware blockers. Need help, thanks!