Conferences are occasional or annual 'meets' organised by a committee, with a group of appointed paper reviewers who review submissions and select the most suitable, original, best etc. papers for publication in a book: 'conference proceedings'. Conferences are self-funded - i.e. people attend because they are interested in the conference subject matter. People who attend pay a registration fee, which provides for e.g. a printed book of proceedings for all registrants. It's like an 'expo' for [insert cool academic subject here]. If you get a paper published, you need to present either a poster or a talk about your document at the event