TOKYO—Two of America’s star Olympians headline Sunday’s events at the Tokyo Games as Simone Biles and Katie Ledecky both begin their quests to rewrite the record books. The U.S. men’s basketball team begins play, while surfing makes its Olympic debut and the women’s skateboarders see their first action. Here are some things to watch. (all times Eastern): Swimming Five-time Olympic gold medalist Katie Ledecky came to Tokyo attempting to break the all-time record of eight gold medals won by a U.S. woman. The first of her five scheduled events is the women’s 400-meter freestyle. Although Ledecky is considered the best women’s distance swimmer in the world, she is expected to face a fierce challenge from Ariarne Titmus of Australia. Ledecky has won six total medals in her first two Olympics and she won her first gold medal at the London Games in 2012 when she was just 15 years old. …