See the glossary definition of Theme

  1. Go to your Dashboard
  2. Click Appearance
  3. Navigate through the available themes by scrolling through the page
  4. Roll the mouse over a theme that interests you
  5. Click Live Preview
  6. You can change the options in the sidebar to modify the theme's taglines, headers, colors, images, etc.
  7. Click Save & Activate in order to choose a theme