1. Log into the store.

2. Copy store URL from your browser address bar.

3. Go to Advanced Settings.

4. Click API Accounts.

5. Click Create API Account.

6. Type the name of the user in the Username box.

7. There you will find API Path box. Copy the part of the value that placed between api.bigcommerce.com and /v3/ as shown.

8. Click Content - modify, Checkout Content - modify, Customers - modify, Customers Login - login, Information Settings - modify, Marketing - modify, Orders - modify, Order Transactions - modify, Products - modify, Themes - modify, Carts - modify.

9. Click the Save button. There will appear a window BigCommerce API Credential with Client ID and Access Token.

10. Add BigCommerce store to your API2Cart account, using credential you've got in steps 2, 7 and 9.