"While bombs are still bursting and flames still pouring from our shattered naval craft a light United States cruiser valiantly moves out to join the fleet and avenge Pearl
Harbor" What does this mean?

Explanation:

I don't know what text this is from, but when Pearl Harbor was attacked, the ships that were docked there and bombed by the Japanese burned for days. I don't know if the passage is referreing to Japanese bombs being dropped or our own bombs exploding on the ships as they burned, but "shattered naval craft" means Navy ships of many kinds. A light cruiser is a Naval warship. On the day Pearl Harbor was attacked, they began trying to move any airplanes and ships that were not destroyed out away from Hawaii.

So even as Pearl Harbor was exploding and burning, a Navy ship moved out of harbor into the Pacific Ocean to join the rest of the Navy in the Pacific to fight back against the Japanese.

Does that all help? Need any other words decoded?