1. Go to User Experience > Branding and Themes.
  2. Under My Themes, click the plus (+) card.
  3. In the Theme Library window, click the theme you want to add.
  4. At the bottom of the Preview window, click Add Theme. The theme is added to your My Themes list.
    Note:

    When you add a theme, a unique theme name is generated. For example, if a theme named 'Focus' already exists, then on creation of a new theme named 'Focus', the unique name will be 'Focus 1' by default. Theme names can be modified after being generated.

    Note: You can also customize an existing theme. For more information, see Customizing a theme.