Short answers, pulled from the story.
The earliest representation of a sail, found in Egypt, dates to circa 3100 BCE. A piece of Mesopotamian pottery from the 6th millennium BCE may depict a bipod mast on a reed boat, but no sail is shown in that image.
Sailing was probably independently invented in at least two regions: Island Southeast Asia and the Mediterranean, including the Nile and other Middle Eastern rivers. The Guayaquil River in Ecuador may represent a third independent site of invention.
Austronesian peoples were using sails before 2000 BCE and expanded from what is now Southern China and Taiwan starting around 3000 BCE. They used outriggers, catamarans, and crab claw sails, navigating with stick charts to colonize islands from Maritime Southeast Asia to Polynesia and Madagascar.
Rome consumed about 150,000 tons of Egyptian grain each year over the first three centuries AD. Transporting it by sail across the Mediterranean was so economical that it cost less to ship grain the full length of the sea than to move the same amount 15 miles by road.
The point of sail is the direction of travel under sail relative to the true wind direction. Key points include close-hauled at roughly 45 degrees off the wind, beam reach at 90 degrees, broad reach at 135 degrees, and running downwind at 180 degrees. Most sailing craft have a no-go zone within about 45 degrees directly into the wind.
Steam-powered vessels gradually replaced sailing ships over the latter half of the 19th century, primarily because steam allowed scheduled services at higher average speeds regardless of wind. Steamships' ability to use the Suez and Panama Canals and to keep reliable schedules made sailing ships uneconomical for commerce.