Subscription Form set up for Dali Theme

Hi..seems recently Dali theme was updated and a Subscription Form was added in the same.

How ever unlike the Subscription form set up details for other themes I could not find any such guide for Dali theme.

Somehow I have managed to add mailchimp code in the customisation settings/subscription form but when ever a user fills up the form with his email ID and clicks subscribe button, it redirects it to a new page where again the email ID details are asked.

How can I change these settings that the user remains on the same page and gets a message that he has been successfully subscribed.

And when he tries to subscribe again then he should get a message that 'he has already subscribed with this email ID"

Can anyone plz help in setting up this form correctly in Dali theme ?