Registering a Sidebar in WordPress

functions.php

// Function to create widgetized area
function meetup_widgetized_area() {
    $args = array(
        'name'          => __('Meetup Widgetized Area', 'sample-child'),
        'id'            => 'meetup-widgetized-area',
        'description'   => 'A sample widegetized area',
        'class'         => '',
        'before_widget' => '<section id="%1$s" class="widget %2$s">',
        'after_widget'  => '</section>',
        'before_title'  =>  '<h2 class="widgettitle">',
        'after_title'   =>  '</h2>',
    );

    register_sidebar($args);
}

// Hook into the widgets_init() function and call our function to register our widgetized area
add_action( 'widgets_init', 'meetup_widgetized_area' );