Here is the correct chronological order of the events you listed from the American Revolutionary War:
- Battles of Lexington and Concord (April 1775)
- Battle of Saratoga (September-October 1777)
- Winter at Valley Forge (Winter 1777-1778)
- Battle of Yorktown (September-October 1781)
So, the chronological order is:
- Battles of Lexington and Concord
- Battle of Saratoga
- Winter at Valley Forge
- Battle of Yorktown