The Cannon was a weapon used on ships in every era of pirates. They were really just a giant more powerful gun. People using the cannons would get a cannonball, put it in the hole in the front of the cannon, fill it with gunpowder, use the ramrod, open the cannon hatchet, puhs it in and aim, light the bomb fuse then it would fire, pull the cannon out, close the hatchet to avoid being hit through it then reapeat. It was a long and tiring process but the damage to the opposing ship was often worth it.
Round shots were just normal cannonballs, they were the first cannonballs and were just dressed stone,and were used throughout sailing times.
Chain shots were a small cannonball tied together by a chain and would be shot out of the cannon and shot at the mast of the enemy ship to try to make them immobile.
Grapeshot is a Anti-personel shot type that is packed into a canvas bag mostly used in naval warfare.
Canister shot is another anti-personel shot type, that unlike grapeshot, would fire smaller and wouldn't rip through the hull of the opposing ship.