> For the complete documentation index, see [llms.txt](https://docs.digitalriver.com/salesforce-b2c-link-cartridge/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-b2c-link-cartridge/2.0/extending-the-salesforce-b2c-link-cartridge.md). # Extending the Salesforce B2C LINK Cartridge ## Custom code {% hint style="info" %} **IMPORTANT**: Follow the instructions below only when you can’t use the cartridge directly, or you need to resolve conflicts with other cartridges on your project. Otherwise, you must compile the client-side scripts and styles, upload the cartridge, and add it to your storefront cartridge path. Cartridge **int\_digitalriver\_sfra** already contains all templates and script changes described in [Custom code](/salesforce-b2c-link-cartridge/2.0/configure-the-salesforce-b2c-link-cartridge.md#custom-code). {% endhint %} ### Templates Make the following changes to the template files: * Template: **cartridge\templates\default\account\payment\addPayment.isml** Add this Digital River script to Drop-in functionality on the page. And apply the changes to Drop-in styles. ``` ``` And apply the changes to Drop-in styles. ``` assets.addCss('/css/digitalRiver.css'); ```

Put the following condition inside the card-body `div`. ``` Include Digital River Drop-In Default Payment form ```

* Template: **cartridge\templates\default\cart\cartTotals.isml**. Include the **Digital River Duty** section in the cart totals template after the discount section. ```

${Resource.msg('label.order.sales.duty','digitalriver', null)}

${pdict.totals.duty.formatted}

```

* Template: **cartridge\templates\default\checkout\billing\paymentOptions\paymentOptionsSummary.isml**.\ Extend the condition with the `‘DIGITAL_RIVER_DROPIN’` payment method. ``` ```

* Template: **cartridge\templates\default\checkout\billing\billing.isml**. Include the Digital River payment options template. ``` ```

* Template: **cartridge\templates\default\checkout\billing\storedPaymentInstruments.isml**. Extend the `card-image` class condition as follows: ``` Digital River - if enabled no cvv needed thus pictures are always shown instead of input … security-code-input goes here ```

* Template: **cartridge\templates\default\checkout\shipping\shippingAddress.isml**. Extend the shipping address form with the email address input field. ```

${Resource.msg('field.customer.email','checkout',null)} aria-describedby="emailInvalidMessage" >

```

* Template: **cartridge\templates\default\checkout\checkout.isml**. \ Include the Digital River styles. ``` assets.addCss('/css/digitalRiver.css'); ```

Add a condition that will control the submit payment button display. ```