iOS app installation (what some people call "side-loading") is done by signing up as a developer and then installing the apps as if you're developing them. You have to refresh them every 7 days in Xcode or they'll get deleted from your phone as that is one of Apple's anti-using-developer-mode-to-actually-install-things measures, and you can only install up to 3 apps this way, though apparently there's some kind of chameleon app that wraps multiple other apps with a menu.