So if you want to make the two original sidebars unavailable, you first need to unregister those sidebars. To do this, add the following to your functions.php file.
[php]//Unregister Sidebars
unregister_sidebar('sidebar');
unregister_sidebar('sidebar-alt');

// Remove Default Genesis Sidebar
remove_action('genesis_sidebar', 'genesis_do_sidebar'); [/php]

Then you need to register your new widget area:
[php]add_action('genesis_sidebar', 'child_do_sidebar');
function child_do_sidebar() { ?>
<?php if ( !function_exists('dynamic_sidebar') || !dynamic_sidebar('Child Sidebar') ){ ?><?php } ?>
<?php }
[/php]

Then add your Child Sidebar:
[php]// Add Child Sidebar
genesis_register_sidebar(array(
'name'=>'Child Sidebar',
'id' => 'sidebar-primary',
'description' => 'This is the primary Child sidebar',
'before_widget' => '<div id="%1$s"><div>',
'after_widget' => "</div></div>n",
'before_title' => '<h4><span>',
'after_title' => "</span></h4>n"
));[/php]

This is rather easy. In your functions.php file, add this one line of code.
[php]// Add Post Thumbnail Support
set_post_thumbnail_size(300, 165, TRUE);[/php]

For more information on set_post_thumbnail_size, see the WordPress Codex, but generally speaking here is the usage:
[php]<?php set_post_thumbnail_size( $width, $height, $crop ); ?> [/php]

Here's how to add the Secondary Navigation to certain pages with the various Genesis options including Fancy Dropdowns, depth, and order. Add this to your functions.php file.

[php]
//just in case: ensures subnav on Genesis Theme Settings is set to true/checked.
$genset=get_option('genesis-settings');
if (!$genset['subnav']) {
$genset['subnav']=1;
update_option('genesis-settings',$genset);
}
//Remove Subnav
remove_action('genesis_after_header', 'genesis_do_subnav');
add_action('genesis_after_header','my_custom_subnav');

function my_custom_subnav () {
$genset['subnav_superfish'] = 1; //1 = Enable Fancy Dropdowns, 0 = Disable
$genset['subnav_home'] = 0; //1 = Display home, 0 = Disable
$genset['subnav_type'] = 'categories'; // pages = List of Pages, categories = List of Categories, nav-menu = Custom Nav Menu
$genset['subnav_pages_sort'] = menu_order; // menu_order = Menu Order, post_title = Title, ID = ID, post_date = Date Created, post_modified = Date Modified, post_author = Author, post_name = Slug
$genset['subnav_categories_sort'] = post-title; // menu_order = Menu Order, post_title = Title, ID = ID, post_date = Date Created, post_modified = Date Modified, post_author = Author, post_name = Slug
$genset['subnav_depth'] = 0; // 0 = No Limit, 1, 2, 3, 4
update_option('genesis-settings',$genset);

$pages = array(1,2,3); //insert whatever page ids, slugs etc.
if (is_page($pages)) {
genesis_do_subnav();
}
}[/php]

Ever get the question, "I placed my widget in the sidebar but it doesn't appear! Why!?" only to discover that they moved the item to the Secondary Sidebar. How about just removing that sidebar altogether? Here's how:

[php]unregister_sidebar('sidebar-alt');[/php]

Sometimes limiting options saves a lot of headaches, questions, and time-wasters. You've delivered on the Statement of Work and to prevent minimal maintenance, it may just be easier to unregister some site layouts. Here's how to do that in Genesis.

[php]// Unregister other site layouts
genesis_unregister_layout( 'content-sidebar' );
genesis_unregister_layout( 'sidebar-content' );
genesis_unregister_layout( 'content-sidebar-sidebar' );
genesis_unregister_layout( 'sidebar-sidebar-content' );
genesis_unregister_layout( 'sidebar-content-sidebar' );[/php]