After Installing the Mailchimp API Module.

Step 1: Go to 'Email Marketing'

Step 2: Under Mailchimp Click on 'Mailchimp' and create a record with mailchimp api-key and mailchimp username (email of mailchimp account owner). Make sure the Mailchimp key and Username should be correct.

After creating the record with correct credentials click on 'Test Connection' button to check connection and if the credentials are right you will have a pop-up of 'Connection Successfull'.

Step 3: Now Create a campaign ,

Step 3.1:If you want to design your template in odoo and attach it to the Campaign

Step 3.2:If you want to use templates designed in Mailchimp , but for this you must have the template designed in mailchimp and the name of that template. Check the box of 'Use Mailchimp Templates'

Example :- I have selected 'Sample template' which I have designed in Mailchimp and its name is 'Sample template'.

Step 4: After entering all the details Click on 'Send To Mailchimp' button to Export the Campaign to Mailchimp and if Successfully Exported you will have 'Exported' check-box checked. After that you can go to Mailchimp and see the Campaign Created

You can see the 'Exported' check-box is true.