A newsletter may be considered to be special website page that, after you have finished editing it (e.g adding pictures and text), it can be emailed to a list of subscribers to that particular newsletter – usually newsletter subscribers are members of your website, but this is not necessarily so. By default your website will have at least one newsletter that people can subscribe to, but, if appropriate, you can create as many different newsletters as you like. An easy way to have members subscribe to a newsletter is to add that particular newsletter's block to your website, then they may simply click on the 'subscribe button'.
This screen gives you some options for managing your newsletters. The tabs along the top, reading 'Sent items', 'drafts', 'newsletters', 'subscriptions', respectively allow you to view sent newsletter articles, view in-progress newsletter articles that have not yet been sent, manage your newsletters (e.g. create new newsletters or edit existing ones), and manage subscriptions to your newsletters. Let's take a look at the 'subscriptions' administration page by clicking on the 'subscriptions' tab.
The subscriptions page allows you to manage subscriptions to your news letters. Although you will probably prefer to let members of your site control their own subscription to newsletters (i.e. rather than you having to manually subscribe tens or hundreds of people), you may want to subscribe some people who are not members of your site. To do this, you can click on the 'import subscriptions' option on the subscriptions page, whereupon you will be able to manually add a list of email address.