First of all, do you have to sing this? May you use a melody you know and create new lyrics about the attack? I'm going to give you suggestions on writing lyrics to a melody you have chosen to use. Now, which parts of the attack do you want to include? Narrow your focus and think of three verses sort of like three paragraphs. Most songs tell a story using show me details like the fire from the burning ship spilled into the harbor rather than the ship started to burn, or poetic devices like simile (the pilot ejected from the destroyed plane like a rocket during blast off) or personification (the fire licked its lips in anticipation of the ship's explosion) or rhyme. Decide which details you want to include such as the first and second waves of Japanese planes and what the planes wanted to hit. You could contrast the loss of life--something like Japan lost 26 men and the US 2400 or more. Write it like a poem at first and then begin to fill in details which will fit your song. Write with the melody in your head at this point and refer to the link I've listed for the details. What a great assignment! Good luck.