Indents set the position of a paragraph between the margins, while tabs allow you to line up text on the page.
You can set left, right first line and hanging indents for selected paragraphs by selecting Indents and Spacing from the Format Menu entering a measurement (measured from the existing margins) in the boxes. The left indent applies to all lines except the first line, so that you can create a ``hanging indent'' by applying different left and first line settings.
You can change the standard tab setting, and set up custom tab stops for individual paragraphs by selecting the Tabs command from the Format menu.