Universal Language Selector changes and translates interface fonts (menus etc) only. It won’t translate your whole site, that’s you job or your contributors job. Most modern browsers are capable of translating any website’s full-text with either built-in features (right click menu in chrome for example) or there are browser extensions for machine translation. Most mobile devices have translation apps to translate text in web pages.
Since machine translation of large bodies of text is often not ideal, there is a language extension bundle that helps your users to write translations for each page in different languages MediaWiki Language Extension Bundle. If you just need machine translation, I’d encourage you to learn how to use your browser’s translate features or install an extension or app to translate not just your site, but any site on the internet.