A single-page layout places several parts of a site on one long page that people move through by scrolling. It is like a brochure where the sections follow one another in a planned order.
A small event page might include the schedule, venue, speakers, and sign-up form all together. Links near the top can jump to each section.
This layout works best when the information is related and not too large. If each section needs its own search-friendly page or a different task, separate pages may be easier to use.