Does each new line begin a new paragraph? Or do you have to add a blank line to start a new paragraph?

If the two lines above do not run together in one paragraph, the answer is a new line starts a new paragraph.

If there is an empty line after the second paragraph ("Or do you..."), then a blank line shows as a blank line. If there is one blank line above this paragraph, then two blank lines are required. . If there is one line with a dot above this paragraph, then that can be used as a paragraph separator.