How to Hide POS Entegratör Admin Menus

function plt_hide_pos_entegrator_menus() {
	//Hide "POS Entegratör".
	remove_menu_page('gurmepos');
	//Hide "POS Entegratör → Dashboard".
	remove_submenu_page('gurmepos', 'gurmepos');
	//Hide "POS Entegratör → Transactions".
	remove_submenu_page('gurmepos', 'edit.php?post_type=gpos_transaction');
	//Hide "POS Entegratör → Payment Methods".
	remove_submenu_page('gurmepos', 'gpos-payment-methods');
	//Hide "POS Entegratör → Settings2".
	remove_submenu_page('gurmepos', 'gpos-settings');
	//Hide "POS Entegratör → Upgrade Pro".
	remove_submenu_page('gurmepos', 'https://posentegrator.com?utm_source=wp_plugin&utm_medium=referal&utm_campaign=sol_menu');
}

add_action('admin_menu', 'plt_hide_pos_entegrator_menus', 11);
Where do I put this code?