How to Hide Wired Impact Volunteer Management Admin Menus

function plt_hide_wired_impact_volunteer_management_menus() {
	//Hide "Volunteer Mgmt".
	remove_menu_page('wi-volunteer-management');
	//Hide "Volunteer Mgmt → Opportunities".
	remove_submenu_page('wi-volunteer-management', 'edit.php?post_type=volunteer_opp');
	//Hide "Volunteer Mgmt → Volunteers".
	remove_submenu_page('wi-volunteer-management', 'wi-volunteer-management-volunteers');
	//Hide "Volunteer Mgmt → Help & Settings".
	remove_submenu_page('wi-volunteer-management', 'wi-volunteer-management-help-settings');
}

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

Where do I put this code?