Go to your Mailchimp > Website > Domains > Extras > API Keys (<a href="http://prntscr.com/xqo78x" target="_blank">http://prntscr.com/xqo78x</a>) then create a key and paste here. You will get the audience ID here: <a href="http://prntscr.com/xqnt5z" target="_blank">http://prntscr.com/xqnt5z</a>