Safari trouble

I am at my college and trying to connect to the Internet, I have a full wifi signal but when I open safari it says you are not connected to the Internet, I went to the it center where the people don't know much about Macs and they said it should redirect to the schools website where I download a certificate. They said I should try firefox but that still didn't work. Does any one know what I should do? One more thing, I was able to get to this page once before but I did not have my pw at the time. I also went to network diagnostics and I chose automatic for my location then I chose airport for my type of connection then I chose NCCPublic which is what students need to connect to but then it says it requires a pw when it doesn't

Ps sorry if I didn't explain well enough I'm writing this on my iPhone