If you’re looking for some help, it’s important to provide as much context as possible so that people are able to assist you. Try to always mention:
Hey @ckrkmz, welcome to the Ghost forum!
Generally, a bit more context would always be appreciated 
In your case, the problem is in the missing Mailgun setup (see “Mailgun is not setup”)
In order to send newsletters, you need to set up Mailgun, since that is used for sending these emails: Why do I have to set up Mailgun for newsletters?
Simply sign up on the Mailgun website (the pay-as-you-go plan is a bit hidden), retrieve your Mailgun API keys, click on the “Edit” button in your Ghost Mailgun settings you see on your screenshot, and you’re good to go.
In your first screenshot, click where it says Publish. There should be a publish and send option.
I have questions in my mind as to why I should pay to send emails.
I recommend having a look at the link I posted – it answers this questions and more:
It seems unreasonable to me to use a mailgun and force it. Not everyone has thousands of users. We want to be able to scale this and force this choice rather than leaving it to the user.
It is up to the user. If you don’t want to use Mailgun, then don’t. If you want to change the fact that Mailgun is the only mail provider natively supported by Ghost, you can contribute to the development of Ghost.
There is no requirement to use Ghost’s built in newsletter delivery feature. Before we released this feature, thousands of people sent their newsletter using all sorts of other services such as Mailchimp, Sendgrid, Convertkit, and many others. You can easily sync your members database to an external newsletter provider via Zapier, or by following our detailed integration guides.
That’s directly from the link above 
