If you'd like to integrate Mailchimp, just follow these steps:


Add a form to your site  

Click on 'Send'

Choose 'add user to a mailing list' from the drop down menu > 

Click on 'Configure'

Click on 'Settings'

Click on 'Setup'

Choose Mailchimp from the drop down list

Enter your username and API key

Don't know your API key?


See here on how to find it - http://kb.mailchimp.com/integrations/api-integrations/about-api-keys