How to Hide Crowdsignal Forms Admin Menus

function plt_hide_crowdsignal_forms_menus() {
	//Hide the "Crowdsignal" menu.
	remove_menu_page('crowdsignal-forms');
	//Hide the "Crowdsignal → Settings" menu.
	remove_submenu_page('crowdsignal-forms', 'crowdsignal-forms-settings');
	//Hide the "Crowdsignal → Getting Started" menu.
	remove_submenu_page('crowdsignal-forms', 'crowdsignal-forms-setup');
}

add_action('admin_menu', 'plt_hide_crowdsignal_forms_menus', 13);

Where do I put this code?