From within the campaign you'd like BigCommerce connected in, click Integrations in the left menu.

Next, on the Integrations page either click Ecommerce to locate BigCommerce, or use the search box in the upper right to search BigCommerce by name.

Once located, click the BigCommerce tile, then on the following page click Connect New Account.

To enable BigCommerce, you will need to enter your Store's Hash and Access Token. If you don't have these, the Store Owner can retrieve them by following the instructions here (see creating "Store-Level API Accounts").

Once retrieved, enter in the Store Hash and Access token into the appropriate field, then click Save in the bottom left.

Saving will complete the connection to BigCommerce. Now you can explore the pre-made dashboard, or start adding BigCommerce widgets to dashboards and reports.