> For the complete documentation index, see [llms.txt](https://docs.digitalriver.com/salesforce-lightning/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.digitalriver.com/salesforce-lightning/salesforce-lightning-b2b-commerce-app-1.2/integrate-the-salesforce-lightning-app/step-17-integrate-the-digital-river-components-into-the-checkout-flow/subflow-configuration/configure-the-checkout-summary-subflow.md).

# Configure the Checkout Summary subflow

## Configure a variable for the saved tax identifier

Use the variable to display saved tax identifiers.

To create a variable:

1. Click **Setup** ![](/files/gdWiI90IBsNQrB7jE9u2).
2. Type `Flows` in the **Quick Find** field click **Flows**.\
   ![](/files/Tz5hQH4WDZg2sDEw1y1P)
3. Scroll down and click **Subflow - Checkout Summary**. The Flow Builder opens in a separate tab.\
   ![](/files/t6d8r08L5VHiAaX0DpTW)
4. Click the **Manager** tab and then click **New Resource**.\
   ![](/files/PWyPOLv3WdiUQVAAUK3w)
5. Enter the following details:
   * Select **Variable** from the **Resource Type** dropdown list.
   * **API Name**: Type `Saved_Tax_Identifier` (or any other name with no restrictions).
   * Select **Text** from the **Data Type** dropdown list.
   * Select the **Available for input** and **Available for output** check boxes.![](/files/ypOs87jNvpUihvIJfE6V)
6. Click **Done**.

{% hint style="warning" %}
You can this variable to display the tax identifier when you[`configure the Checkout Summary subflow`](#configure-the-checkout-summary-subflow).
{% endhint %}

## Configure the Checkout Summary subflow

Use the Checkout Summary subflow to add support for US tax certificates and tax identifiers. To add custom components to the Checkout Summary subflow:

1. From the **Manager** tab, double-click the **Cart to Order Summary** screen.
2. Delete all OOTB components from the subflow except the **Ship To** and **Delivery Method** components.
3. Type `drb2b_drUtil` in the **Search components** field and click **drb2b\_drUtil**.\
   ![](/files/0cQy5s9zAy6aZxQ5VP6J)
4. Drag the **drb2b\_drUtil** to where you want it to appear on the Edit Screen.
5. Type `drb2b_drUtil` in the **API Name** field.\
   ![](/files/5I1Zo4vCGv0Cyr7JiFeE)
6. Type `drb2b_taxIdentifier` in the **Search components** field and click **drb2b\_taxIdentifier**.\
   ![](/files/ms7lrbXiCZmiSwhw5qxv)
7. Drag the **drb2b\_taxIdentifier** to where you want it to appear on the Edit Screen.
8. Enter the following details:
   * **API Name**: Type `Tax_Identifier` (or any other name with no restrictions).
   * **Cart Id**: Type `{!cartId}`.
   * **Selected Tax Identifier**: Type `{!Saved_Tax_Identifier}`.
   * Click **Advanced**, select the **Manually assigned variables** check box, and type `{!Saved_Tax_Identifier}` in the **Selected Tax Identifier** field.![](/files/lFczN3RBUbDpjb3VHMVO)
9. Type `drb2b_drTermsElement` in the **Search components** field and click **drb2b\_drTermsElement**.\
   ![](/files/jCJZDl6n3EDqFqsafpga)
10. Drag the **drb2b\_drTermsElement** to where you want it to appear on the Edit Screen.
11. Enter the following details:
    * **API Name**: Type `DR_Terms` (or any other name with no restrictions).
    * **Cart Id**: Type `{!cartId}`.
    * **Bypass Validation**: Type `{!$GlobalConstant.True}` or`{!$GlobalConstant.False}`. By default, this value should be `False`. See [DR terms component](/salesforce-lightning/salesforce-lightning-b2b-commerce-app-1.2/extend-the-salesforce-lightning-app/customizing-the-lightning-web-components/components/dr-terms-component.md) for more information.\
      ![](/files/epKq7RAXvYlsNywLHAZH)
12. Click **Done**.
13. Click **Save as**.
14. Enter the name of the custom subflow in the **Flow Label** field (for example, `DR Checkout Summary`) and click **Save**.\
    ![](/files/G7HwENF2lIofeqYuyBdm)
15. Click **Activate**.\
    ![](/files/9iLbhcCaXz5BezHnixf7)