Style selection basics
The first five icons at the top of the Styles and Formatting window select the category of styles to work on. Click on one of these icons to display a list of styles in that category, such as paragraph or character styles, in the main window.
To apply a character style to existing text, select the text and then double-click on the name of the style in the Character Styles list. To apply any other style, put the cursor in the paragraph, frame, or page you want to modify and double-click on the name of the style in the corresponding section. You can select more than one paragraph or frame and apply the same style to all of them at the same time.