There are two main parts to this process. First, we have to provide information about the newsletter to the site visitors and ask them to subscribe to the newsletter. This is the step where we build the audience for the site. Then, we have to create a newsletter and send it to the subscribers.

We started the process by building a list. Lists allow us to categorize the subscribers into different groups. We can have multiple email lists on a site and ask the visitors to subscribe to one or more lists to get different content from each list. The plugin provides a pre-built interface to configure lists. We added one list called Weekly Newsletter Subscribers and configured the settings to show it on the subscription form. These lists are stored in the newsletter_subscription_lists key in the wp_options table in your database.

By default, lists will not be shown in the subscription form. The administrators have to add users internally to specific lists. Since we configured it to show on the subscription form, users will be allowed to select the necessary lists using the checkbox fields. Then we used the shortcode of this plugin to display the subscription form on the frontend. The visitors can view details and enter their email addresses in order to subscribe to the list. Once a user clicks the Subscribe button, the user's email will be stored in a custom table called wp_newsletter and an email will be sent to confirm the subscription.

By default, this plugin uses the Single Opt-In method, where we directly add the email address to our list as soon as a user hits the Subscribe button. However, this process can lead to issues as people can use other people's email addresses to subscribe. So, we changed the opt-in method to Double Opt-In. In this case, we only add the user's own email address to our list. However, it will not be used in newsletters until the user confirms the subscription by clicking the link in the email sent by the plugin. Once the user confirms the email, their subscription will be marked as confirmed. The user emails and their subscribed lists will be stored in the wp_newsletter table.

After getting subscribers for the lists, we created the newsletter to be sent to those subscribers. This plugin provides several built-in templates with default content. We selected the Default template in this scenario. Then, we adjusted the header and content of the newsletter using a Rich Text Editor. We also added the latest posts list to the newsletter by selecting the pre-built options provided by this plugin. Once the newsletter content is customized and saved, the plugin will store the details in a custom table called wp_newsletter_emails. 

Finally, we created the Send Now button to send the newsletter email. The interface shows how many subscribers are eligible to get the email. Once the button is clicked, the plugin will start sending the email to the subscribers to that list. The process will take a considerable amount of time, and the progress will be shown until it's completed. 

Now we have successfully built an audience for the site using a newsletter and started sending the content to the subscribers. We can also use the Statistics section of the Newsletter menu to see details such as how many people clicked and opened the emails.