Problem with subscription form before launching my blog. Help appreciated

I am using wordpress and Astra free template for my blog. On the template there was a preset email subscription form (Spectra) that I want to keep for my blog.

However, I dont know how to make that form work. I understood I need to download MailChimp and somehow connect that existing form to it. I have the account to mailchimp and the plugin but I am struggling to find how.

Also, once I hopefully manage to make it work, how do I see who and how many have signed up etc. Would appreciate any help, I'm not very tech savy when it comes to building websites.