Tips on Customizing EasySecure Simple Gallery

How to Hide EasySecure Simple Gallery Admin Menus

function plt_hide_easysecure_simple_gallery_menus() {
	//Hide the "Galleries" menu.
	remove_menu_page('edit.php?post_type=easysiga_gallery');
	//Hide the "Galleries → Galleries" menu.
	remove_submenu_page('edit.php?post_type=easysiga_gallery', 'edit.php?post_type=easysiga_gallery');
	//Hide the "Galleries → Add New Gallery" menu.
	remove_submenu_page('edit.php?post_type=easysiga_gallery', 'post-new.php?post_type=easysiga_gallery');
}

add_action('admin_menu', 'plt_hide_easysecure_simple_gallery_menus', 15);

Where do I put this code?

How to Hide the "Gallery Settings" Meta Box

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

	//Hide the "Gallery Settings" meta box.
	remove_meta_box('easysiga_gallery_meta', $screen->id, 'normal');
}

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