1. On n8n's main dashboard, click the 'Credentials' tab.
2. After that, click 'Add Credential' in the top-right corner.
3. Browse the list of apps, then select 'WhatsApp API' from the available options.
4. Subsequently, click 'Continue' to proceed.
5. Following that, prepare your WhatsApp Access Token and then enter it into the provided input field.
6. Provide your 'Business Account ID' afterwards. Type it into the next input box.
7. Once done, click 'Save' to apply the changes.
8. Finally, your n8n account will be integrated with the WhatsApp API.