I’d suggest you start the video just to see how a State Funeral is conducted. First, Kennedy’s casket was loaded onto a caisson– a wheeled, horse-drawn cart used in the early years of war to move artillery pieces. Behind the Casket a soldier leads the “cap horse,” a riderless horse with the riding boots inserted into the stirrups backwards, which is used in military funerals to indicate that a high-ranking officer has been killed. The explanation of this tradition is found here.
If you skip ahead then to 5:00 minutes, you will see the most touching scene of the entire funeral.