Karl,
Your English is great. Thank you for your business.
The newsletter bar is set to work with MailChimp, which is a email service that is free for you to use for lists of up to 2,000 addresses or 12,000 emails per month.
MailChimp will collect all your addresses into a list for you. It can send a welcome email when someone signs up and take care of list management for when people unsubscribe.
You can also download your list at any time if you need the emails for some other purpose.
If you need to use another service you can. You’ll need to edit the newsletter-bar.php file that comes in the theme to replace MailChimp’s sign up box with the one for your service.
If you’d like to store the email addresses inside WordPress that can be done as well. You’ll need to use a plugin like Gravity Forms and also edit the newsletter-bar.php file so it’ll work with the plugin.
If you need any other help or have other questions, just let me know.
Thanks,
Bill