I want to group other fields into the hidden address section (or change their order)

If you have some new fields regarding the address, that you added (within your theme or using a plugin), for example: PO Box, Address 3, Address suffix... you may want to group them with the other address fields that are not shown in the beginning.

Or you may want to change the order, for example, set the county first.

To do that, you have to put a piece of code into your functions.php theme file.
This code is into two parts: one for the billing address, and one for the shipping address :

For the billing address: This example shows how to place the (existing) billing_number field and the billing_neighborhood field at the exact location you want into the form. You may change those examples with your own field names. Or just change the order of the native WooCommerce fields.

add_filter('woogoogad_billing_fields_to_group_filter', 'my_billing_fields_to_group');
function my_billing_fields_to_group()
{
	//Return an array of the name of the fields you want to group, in the order you want
	return array(
		'billing_address_1',
		'billing_number', //example of an existing "billing_number" field to place after the billing_address_1 field
		'billing_address_2',
		'billing_city',
		'billing_neighborhood', //another example
		'billing_state',
		'billing_postcode',
		'billing_country'
	);
}

For the shipping address: Same example, for the shipping address.

add_filter('woogoogad_shipping_fields_to_group_filter', 'my_shipping_fields_to_group');
function my_shipping_fields_to_group()
{
	//Return an array of the name of the fields you want to group, in the order you want
	return array(
		'shipping_address_1',
		'shipping_number',
		'shipping_address_2',
		'shipping_city',
		'shipping_neighborhood',
		'shipping_state',
		'shipping_postcode',
		'shipping_country'
	);
}