In order to start using the Swift Mailer module to send your emails, you need to do is enable the module and supply your SMTP settings. If you don't know this information you will need to contact your hosting provider. Note: not all hosting providers offer an SMTP service.
As shown in the screenshot, there are a number of fields for you to fill in. These should all be supplied by your hosting provider or email service. Speaking from experience, you may find it a bit of a struggle to find the right combination of settings. It can take a fair bit of get configured with the nuances of your SMTP server. If you are unsure about the authentication procedure, try systematically choosing one at a time and sending yourself a test email, as shown in the screenshot below.
Confirm everything's working
To check that everything is working as it should, click on the "Test" tab. That page lets you send emails to yourself in various formats.
We've tried to include some helpful error messages if the emails are not sent out, but they are not exhaustive. If you run into trouble, you might want to try contacting your hosting provider for further help.