If you've created (or plan on creating) a multiple SKU bundle, you must activate the app's Cart Integration setting. Cart integration essentially allows Bundle Builder to work to its full potential with your theme's cart, which is fundamental for processing Multiple SKU bundles.

Without this integration in place, customers who add multiple SKU bundles to their cart will face issues at the checkout stage. For the majority of Shopify merchants, activating Cart Integration is as easy as clicking a button!

However, if you use a custom theme (i.e. a theme not purchased through Shopify's Theme Store), then you may have to manually integrate the cart using CSS code.

In this guide, we'll go over the steps required to locate the Cart Integration setting, and the activation process (automatic and manual integration).

If you're using a Shopify Theme Store theme, then you can activate the Cart Integration setting automatically using the below steps:

Step 1: Under the Apps menu, click Bundle Builder's Settings.

Step 2: Click Cart integration to continue to the cart integration settings page.

Step 3: Locate your live theme and click Activate.

Note: The table on this page shows your current theme (Live) and other available themes you have added. Find your theme's name in the Theme column and click the Activate button under the App extension column. You will need to activate cart integration for every new theme you use with Bundle Builder.

Step 4: You will be shown a message directing you to your Theme Editor for the next step. Just click Got it! to proceed.

Tip: After you activate the app extension, the Activate button will change to Settings. Clicking Settings will direct you to the App embeds section, which is where you can manage your cart integration.

Step 5: Ensure Cart Integration is enabled and Save your progress before leaving the page. By default, the Cart Integration toggle should be in the on position. If it's not, simply click it to activate.

Congratulations! Your customers will now be able to successfully add Multiple SKU bundles to their cart!

While you're on this page, you can configure your cart integration to change many of the design elements of your cart, including fonts, colors, and borders. To learn more about this optional step, read our Getting Started guide: How to configure Cart Integration

If you're using a custom theme (i.e. a theme not purchased through the Shopify Theme Store), then you may have to activate cart integration manually. To locate the manual cart integration settings:

Step 1: Under the Apps menu, click Bundle Builder's Settings.

Step 2: Click Cart integration to continue to the cart integration settings page.

Step 3: Locate your live theme and click Activate.

Note: The table on this page shows your current theme (Live) and other available themes you have added. Find your theme's name in the Theme column and click the Activate button under the App extension column. You will need to activate cart integration for every new theme you use with Bundle Builder.

Step 4: You will be shown a message directing you to your Theme Editor for the next step. Just click Got it! to proceed.

Tip: After you activate the app extension, the Activate button will change to Settings. Clicking Settings will direct you to the App embeds section, which is where you can manage your cart integration.

Step 5: Scroll right to the bottom of the App embeds window and click Cart Integration - Manual to activate it.

Step 6: Activating Cart Integration - Manual will open up several settings underneath. To finish successfully integrating the cart, you will need to enter CSS selectors into each of these fields.

Step 7: Save your changes.

Congratulations! Your customers will now be able to successfully add Multiple SKU bundles to their cart!

If you need any further assistance with using CSS code, then we suggest reaching out to a Shopify Expert to help you with the task. HeyCarson and StoreTasker are recommended partners of Bundle Builder - both specializing in website development and offering free quotes for their services.

Now that your bundles are set up and working correctly you can spend a bit of time making sure they are performing as you'd expect. To get the best experience from Bundle Builder, we recommend checking out some of these optional next steps: