It's a good idea before you press schedule on an email campaign to send the email to yourself or a colleague to give it a final check.
To do this click on the 'Send test email' button located underneath the Sender Details field.
Then enter the email address you wish to send the test email to.
If you want to send the test to multiple people just add a semicolon between the email address. Please note, you do not need to put a space between the email addresses, the semicolon will seperate them.