how to use add_theme_support wordpress code example

Example 1: add theme support wordpress

add_theme_support( 'starter-content', array(
    // Place widgets in the desired locations (such as sidebar or footer).
    // Example widgets: archives, calendar, categories, meta, recent-comments, recent-posts, 
    //                  search, text_business_info, text_about
    'widgets'     => array( 'sidebar-1' => array( 'search', 'categories', 'meta'), ),
    // Specify pages to create, and optionally add custom thumbnails to them.
    // Note: For thumbnails, use attachment symbolic references in {{double-curly-braces}}.
    // Post options: post_type, post_title, post_excerpt, post_name (slug), post_content, 
    //               menu_order, comment_status, thumbnail (featured image ID), and template
    'posts'       => array( 'home', 'about', 'blog' => array( 'thumbnail' => '{{image-cafe}}' ), ),
    // Create custom image attachments used as post thumbnails for pages.
    // Note: You can reference these attachment IDs in the posts section above. Example: {{image-cafe}}
    'attachments' => array( 'image-cafe' => array( 'post_title' => 'Cafe', 'file' => 'assets/images/cafe.jpg' ), ),
    // Assign options defaults, such as front page settings.
    // The 'show_on_front' value can be 'page' to show a specified page, or 'posts' to show your latest posts.
    // Note: Use page ID symbolic references from the posts section above wrapped in {{double-curly-braces}}.
    'options'     => array( 'show_on_front'  => 'page', 'page_on_front' => '{{home}}', 'page_for_posts' => '{{blog}}', ),
    // Set the theme mods.
    'theme_mods'  => array( 'panel_1' => '{{about}}' ),
    // Set up nav menus.
    'nav_menus'   => array( 'top' => array( 'name' => 'Top Menu', 'items' => array( 'link_home', 'page_about', 'page_blog' )), ),
) );

Example 2: add_theme_support

$defaults = array(
    'default-image'          => '',
    'default-preset'         => 'default', // 'default', 'fill', 'fit', 'repeat', 'custom'
    'default-position-x'     => 'left',    // 'left', 'center', 'right'
    'default-position-y'     => 'top',     // 'top', 'center', 'bottom'
    'default-size'           => 'auto',    // 'auto', 'contain', 'cover'
    'default-repeat'         => 'repeat',  // 'repeat-x', 'repeat-y', 'repeat', 'no-repeat'
    'default-attachment'     => 'scroll',  // 'scroll', 'fixed'
    'default-color'          => '',
    'wp-head-callback'       => '_custom_background_cb',
    'admin-head-callback'    => '',
    'admin-preview-callback' => '',
);
add_theme_support( 'custom-background', $defaults );