How to Hide Ultimate Cursor – Best Cursor Animation Plugin for WordPress Admin Menus

function plt_hide_ultimate_cursor_menus() {
	//Hide "Ultimate Cursor".
	remove_menu_page('ultimate-cursor');
	//Hide "Ultimate Cursor → Welcome".
	remove_submenu_page('ultimate-cursor', 'ultimate-cursor');
	//Hide "Ultimate Cursor → Settings".
	remove_submenu_page('ultimate-cursor', 'admin.php?page=ultimate-cursor&sub_page=settings');
	//Hide "Ultimate Cursor → Multiple Cursors".
	remove_submenu_page('ultimate-cursor', 'admin.php?page=ultimate-cursor&sub_page=settings&tab=multiple');
	//Hide "Ultimate Cursor → Discussions".
	remove_submenu_page('ultimate-cursor', 'https://wordpress.org/support/plugin/ultimate-cursor');
}

add_action('admin_menu', 'plt_hide_ultimate_cursor_menus', 21);

Where do I put this code?