It's very simple to activate the newsletter signup feature and start collecting e-mails for your newsletter database. You can do this in two ways:
Activate newsletter signup from your website list
Activate using the on/off switch as marked on the picture above.
Activate newsletter signup from the settings menu
Navigate to the settings menu and press "newsletter signup". Activate using the on/off switch and press save.
PS: Don't forget to download your e-mail permissions frequently and add them to your newsletter database.