Short answers, pulled from the story.
Apollo 4 served as the first test flight of the Saturn V rocket under an all-up testing approach. This uncrewed mission verified that every stage and component functioned perfectly on its initial attempt.
The Apollo 4 launch occurred on the 9th of November 1967 at 7:00am EST. The seven-hour countdown sequence began earlier on the 6th of November 1967 with propellant loading.
George Mueller ordered the all-up testing approach because he believed it accelerated the Air Force Minuteman ICBM program successfully. This decision required every component to work together during the very first flight.
The spacecraft landed approximately 95 nautical miles northwest of Midway Island in the North Pacific Ocean. Recovery operations began within two hours aboard the aircraft carrier Hornet which retrieved the capsule and one parachute.
Inspectors discovered 1,407 errors in the spacecraft including haphazardly routed wires and an extra bolt inside a J-2 engine. A meeting in March 1967 disclosed twelve hundred problems with the Saturn V vehicle.