perch shop checkout via api

I was able to complete the checkout via web.

now I need to do do same thing via api. every request would only have single item, to checkout.

request sent is product id, color, size, quantity, user id (customer id). api is suppose to add item to cart, I was able to do this using

perch_shop_add_to_cart($product_id);

Now I need to set shipping address for the order, and checkout without paypal. I know I could do below

perch_shop_checkout('manual', [
        'return_url' => '/shop/thanks',
            'cancel_url' => '/shop/cancel',
    ]);

but , I believe I also need to attach address to the order? how do it do that?

is there anything else I am missing in above process?