Help with Mailchimp

Hi, i’m setting up my website. I would like to use this plugin with the fifty theme. I use Mailchimp and its plugin for my newsletter. I’m trying to find the shortcode in the plugin settings but there is nothing in the settings page.

Do I have to search in the plugin code? and in case do you know exactly in which file I have to look for the code? there are a lot of different files in the plugin directory.

Also which part of the code do i need to paste in “subscrive form” setting?

Thank you in advance

Claudia