From the Email Editor, click on the "Test" icon from the left-hand navigation bar. After selecting this icon, a "Send a Test" modal will open, and you can enter your email, plus four more. Once completed, click "OK."
Email tests come from firstname.lastname@example.org and email@example.com, so you should mark these emails off as "Not Spam," i.e., whitelist this email. Because you will continue to test emails, this will speed up the process and avoid any spam filters from being triggered while you are in the testing phase.
Another area you can send a test email is from the "Schedule Email Modal" by clicking the Calendar icon on the left side navigation bar.
Select the "Send Test" button, add in your email(s), and click "OK."