1. Login to your Mailchimp account
2. Get API Key
Click to account section in the header and click to menu "Account"
Then, click "Extras" -> "API Key" to go to the API page. Please copy the existing API or create the new API key you want.
3. Get Listing ID
Please click to menu "Audience" and click to "Settings" item in drop-down of "Manage Audience"
Then, click to menu "Settings" -> "Audience name and defaults" go get List ID
Example for MailChimp profile