Cannot create my own template

I am interested in purchasing the premium package. I love MailPoet!! It does almost everything I can dream of – almost. One thing I really want to be able to do is to design my own template for emails being sent out. It will really make or break whether my business email looks professional or silly. I would love to have my business represented fairly and appropriately online. If I can’t find a way to do that, I will have to use another email service. I see there are instructions for MailPoet version 2, but not MailPoet version 3.

How can I make my own template? Please advise.