A paragraph style includes font and spacing settings applied to an entire paragraph, not a text selection.
To apply a paragraph style:
While editing a page, position the insertion point anywhere within a paragraph you'd like to apply a paragraph style to.
You can also select multiple paragraphs. The selection can start anywhere in one paragraph and end anywhere in another.
Click the Paragraph Style (paragraph mark) button and then choose a paragraph style from pop-up menu.
After choosing a paragraph style, the selected paragraph changes to that style.