Tips on Customizing Ebook Store

How to Hide eBook store Admin Menus

function plt_hide_ebook_store_menus() {
	//Hide "Settings → Ebook Store".
	remove_submenu_page('options-general.php', 'ebook_options.php');

	//Hide "Ebook Store".
	remove_menu_page('edit.php?post_type=ebook');
	//Hide "Ebook Store → Ebooks".
	remove_submenu_page('edit.php?post_type=ebook', 'edit.php?post_type=ebook');
	//Hide "Ebook Store → Add New Ebook Item".
	remove_submenu_page('edit.php?post_type=ebook', 'post-new.php?post_type=ebook');
	//Hide "Ebook Store → Ebook Categories".
	remove_submenu_page('edit.php?post_type=ebook', 'edit-tags.php?taxonomy=ebook_category&post_type=ebook');
	//Hide "Ebook Store → Authors".
	remove_submenu_page('edit.php?post_type=ebook', 'edit.php?post_type=ebook_author');
	//Hide "Ebook Store → Publishers".
	remove_submenu_page('edit.php?post_type=ebook', 'edit.php?post_type=ebook_publisher');
	//Hide "Ebook Store → Orders".
	remove_submenu_page('edit.php?post_type=ebook', 'edit.php?post_type=ebook_order');
	//Hide "Ebook Store → Orders - Add New".
	remove_submenu_page('edit.php?post_type=ebook', 'ebook-store-add-order-page');
	//Hide "Ebook Store → Orders - Reports".
	remove_submenu_page('edit.php?post_type=ebook', 'ebook-store-order_reports');
	//Hide "Ebook Store → Orders - New Issue".
	remove_submenu_page('edit.php?post_type=ebook', 'ebook-store-add-issue-page');
	//Hide "Ebook Store → Settings".
	remove_submenu_page('edit.php?post_type=ebook', 'settings-page');
}

add_action('admin_menu', 'plt_hide_ebook_store_menus', 11);

Where do I put this code?

How to Hide eBook store Meta Boxes

function plt_hide_ebook_store_metaboxes() {
	$screen = get_current_screen();
	if ( !$screen ) {
		return;
	}

	//Hide the "Ebook Store - Click on Ebook to embed it" meta box.
	remove_meta_box('ebook_wp_embed_ebook', $screen->id, 'advanced');
	//Hide the "Ebook Details" meta box.
	remove_meta_box('ebook_wp_custom_attachment', $screen->id, 'advanced');
	//Hide the "Order details" meta box.
	remove_meta_box('ebook_order_box', $screen->id, 'advanced');
}

add_action('add_meta_boxes', 'plt_hide_ebook_store_metaboxes', 20);