To access your API Key and List ID to your MailChimp account you'll have to go to their support articles About API Keys and Finding Your List ID
Once you have your API Key and List ID, you're ready to connect your OSP account. Do not move on to the next step until you have completed the above.
- Log in to Online Sales Pro. From the Dashboard, click on the Edit tab. Then click on Autoresponder.
- On the right hand side, click Manage Account and then on Autoresponders.
- Click on MailChimp from the icons of the third-party autoresponders.
- Enter your MailChimp API Key and List ID. (Note: These are provided by MailChimp and must match exactly to work.)
- Click the Integrate button to save.