How did the french at yorktown? (during the revolutionary war)

The French helped at Yorktown by supplying troops as well as ammunition and guns to the American Army. The French had held a grudge against the British from the Seven Years' War and so they decided to help the Americans in the Revolutionary War. The French also brought with them a fleet of 28 ships. At the end, there were 8,800 Americans and 10,800 French soldiers were against 7,500 British soldiers.

Hope this helps.