magento#589: Add a tutorial for the checkout workflow

Author: atwixfirster

guides/v2.3/graphql/tutorials/checkout/checkout-shipping-address.md

@@ -107,5 +107,134 @@ where
 }
 ```
 
+### Use for shipping a defined billing address
+
+See [Add a new address for billing and shipping]({{ page.baseurl }}/graphql/tutorials/checkout/checkout-billing-address.html) topic.
+
 {:.bs-callout .bs-callout-info}
 Send customer's authorization token in the `Authorization` parameter of the header if you set shipping address for a registered customer. See ["Get customer authorization token"]({{ page.baseurl }}/graphql/get-customer-authorization-token.html) to get more details.
+
+### Use the existing customer's address
+
+Use a query below to retrieve the list of customer addresses:
+
+**Request**
+
+```text
+query {
+  customer {
+    addresses {
+      id
+      default_billing
+      default_shipping
+    }
+  }
+}
+```
+
+**Response**
+
+```text
+{
+  "data": {
+    "customer": {
+      "addresses": [
+        {
+          "id": 2,
+          "default_billing": true,
+          "default_shipping": false
+        },
+        {
+          "id": 3,
+          "default_billing": false,
+          "default_shipping": false
+        },
+        {
+          "id": 4,
+          "default_billing": false,
+          "default_shipping": true
+        }
+      ]
+    }
+  }
+}
+```
+
+Define `customer_address_id` to assign the existing customer address. 
+
+**Request**
+
+```text
+mutation {
+  setShippingAddressesOnCart(
+    input: {
+      cart_id: "{{ CART_ID }}"
+      shipping_addresses: {
+          customer_address_id: {{ CUSTOMER_ADDRESS_ID }}
+      }
+    }
+  ) {
+    cart {
+      shipping_addresses {
+        firstname
+        lastname
+        company
+        street
+        city
+        region {
+          code
+          label
+        }
+        postcode
+        telephone
+        country 
+        {
+          code
+          label
+        }
+        address_type
+      }
+    }
+  }
+}
+```
+
+where 
+`{{ CART_ID }}` - shopping cart unique ID from [Step 2. Create empty cart]({{ page.baseurl }}/graphql/tutorials/checkout/checkout-add-product-to-cart.html).
+`{{ CUSTOMER_ADDRESS_ID }}` - customer address ID (value from `entity_id` field of `customer_address_entity` table).
+
+**Response**
+
+```json
+{
+  "data": {
+    "setShippingAddressesOnCart": {
+      "cart": {
+        "shipping_addresses": [
+          {
+            "firstname": "John",
+            "lastname": "Doe",
+            "company": "Company Name",
+            "street": [
+              "320 N Crescent Dr",
+              "Beverly Hills"
+            ],
+            "city": "Los Angeles",
+            "region": {
+              "code": "CA",
+              "label": "California"
+            },
+            "postcode": "90210",
+            "telephone": "123-456-0000",
+            "country": {
+              "code": "US",
+              "label": "US"
+            },
+            "address_type": "SHIPPING"
+          }
+        ]
+      }
+    }
+  }
+}
+```