Most marketing teams will choose a template (there are many available online—just Google!), then fill them in based on their observations about their customers.Obviously, if you’re running a new business and you’ve got no customers yet, you won’t be able to rely on patterns that you draw from actual customers. That’s perfectly fine—just fill in the template based on your understanding of your potential customers, and you can always revisit your customer personas further down the road and tweak them when necessary.