Complex sentence: The couple have their wedding at the Burrow and some guests include Luna Lovegood and her father and also Viktor Krum who was a fellow Tri-Wizard Champion along with Fleur and Harry, death eaters attack at their wedding reception and Harry, Ron and Hermione flee.
Split into simpler sentences: The couple have their wedding at the Burrow and some guests include Luna Lovegood and her father and also Viktor Krum who was a fellow Tri-Wizard Champion along with Fleur and Harry. Death Eaters attack at their wedding reception and Harry, Ron and Hermione flee.