Now you have all the settings and preparation done, the final step is to connect to MailChimp and create the new integration. In the Kartris back end, go to "Miscelleneous > MailChimp". This page should show the relevant MailChimp settings you've entered. You can name the store, enter your store's domain and your email address and then push the 'Create MailChimp Store' button.

This sends a request through to the MailChimp API which actually creates the new store record there.

You should see a confirmation of the result. If you get a message saying the Id already exists, that suggests that you already created this store previously.