Adding a new widget area

@wildvolets

Firstly you should create a child_theme – and copy over header.php and create a blank functions.php

Add the following to functions.php

<?php
// Custom widget area.
 register_sidebar( array(
    'name' => __( 'Custom Widget Area'),
    'id' => 'custom-widget-area',
    'description' => __( 'An optional custom widget area for your site', 'twentyten' ),
    'before_widget' => '<li id="%1$s" class="widget-container %2$s">',
    'after_widget' => "</li>",
    'before_title' => '<h3 class="widget-title">',
    'after_title' => '</h3>',
) );

then in header.php find
</header><!-- #masthead .site-header -->

and add the following code after it

<?php
      if ( !function_exists('dynamic_sidebar') || !dynamic_sidebar('Custom Widget Area') ) : ?>
<?php endif; ?>