You need to add the script code found in the App settings section here to Script Manager section of your Bigcommerce store:

Depending on Theme you are using in your Bigcommerce store please click the radio button like on the screenshot above and then copy the script to Script Manager:

• Click Storefront on the left side of your Bigcommerce store admin panel.

• Then Script Manager.

• And then click Create a Script.

• On the next page you need to name the script (for your internal use) e.g. Unlimited Upsell

• Description can be skipped.

• Choose Footer for Location on page.

• Choose All Pages for the option Select pages where script will be added.

• Choose Essential for Script category.

• Choose Script and insert the script from Settings section of our app:

• Click Save.