Ios 7 help I can't figure it out?

I have it downloaded off mega but I can't figure out how to get it in my iPhone 4S

FYI, you won't be able to install iOS 7 unless you register your device's UDID with a developer account through a site like http://www.udid.in/.It's $5, and then you also don't need to worry about Apple disabling your device for running unreleased software.