How to Hide Gallery Custom Links Admin Menus

function plt_hide_gallery_custom_links_menus() {
	//Hide the "Meow Apps" menu.
	remove_menu_page('meowapps-main-menu');
	//Hide the "Meow Apps → Dashboard" menu.
	remove_submenu_page('meowapps-main-menu', 'meowapps-main-menu');
	//Hide the "Meow Apps → Custom Links" menu.
	remove_submenu_page('meowapps-main-menu', 'mgcl_settings');
}

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

Where do I put this code?