How to Hide PageLayer Admin Menus

function plt_hide_pagelayer_menus() {
	//Hide the "Pagelayer" menu.
	remove_menu_page('pagelayer');
	//Hide the "Pagelayer → Settings" menu.
	remove_submenu_page('pagelayer', 'pagelayer');
	//Hide the "Pagelayer → Go Pro" menu.
	remove_submenu_page('pagelayer', 'https://pagelayer.com/features#compare');
}

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

Where do I put this code?