auto generate order note

Dear support team,
by far, you provide the best plugin for editing the checkout page.
However, I need to know how to access a field. I need to generate an auto order note, I’m using woocommerce hook, and it works fine, but I need to do if statement with one of your field. As you see, I added ‘_billing_select_a_branch’, an id of one of the fields created by your plugin, but it didn’t work at all, it will just generate the ‘test’ note. Please, can you help with this? I just need to access the field and its value.

add_action( 'woocommerce_new_order', 'add_engraving_notes' );
function add_engraving_notes( $order_id ) {

$order = wc_get_order( $order_id );

// The text for the note
// 

if(_billing_select_a_branch == 'juffair')
$note = 'alraya mall';
	
	elseif(_billing_select_a_branch == 'abc')
$note = 'abc branch';
	
	else{
		$note = 'test';
	}

// Add the note
$order->add_order_note( $note );

// Save the data
$order->save();
}

The page I need help with: [log in to see the link]