How to Hide ApexIdx Admin Menus

function plt_hide_apex_idx_menus() {
	//Hide "Apex IDX".
	remove_menu_page('apexApiVerification');
	//Hide "Apex IDX → i. API Console".
	remove_submenu_page('apexApiVerification', 'apexApiVerification');
	//Hide "Apex IDX → ii. Widgets".
	remove_submenu_page('apexApiVerification', 'RTapexAgentWidgets');
	//Hide "Apex IDX → iii. Idx Pages".
	remove_submenu_page('apexApiVerification', 'RTapexAgentDefaultPages');
}

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

Where do I put this code?