Complex sentence: While buying school supplies, Harry and the Weasley family encounter Rubeus Hagrid and Hermione Granger, and they attend a book-signing by celebrity wizard Gilderoy Lockhart, who announces he will be the new Defence Against the Dark Arts teacher.
Split into simpler sentences: While buying school supplies, Harold and the Weasley family encounter Rubeus Hagrid and Hermione Granger. They then attend a book-signing by celebrity wizard Gilderoy Lockhart, who announces he will be the new Defence Against the Dark Arts teacher.