What does one by land two by sea mean?

"No body actually knows different story's been pasted on for years

nobody actually knows if the British came by land or by sea different story's been pasted on for many years." Is NOT true. the real answer is..

They would hang two lanterns, light one if by land, two if by sea. Of course there wasn't a "3" because they didn't have airplanes!

When it was night and two lanterns were lit and Paul Revere saw it, he jumped on his horse, and declared, "The British are coming!". Two other men joined his escapade to save the country.