HTML Templates: Show First Name in Order Confirmation

I've created an order confirmation for groups with a single barcode that they will bring with them to performances instead of printing out a stack of tickets. It's working great and now I would love to personalize it but can't figure out how. Right now it reads "Dear ORG NAME," and I'd like it to read "Dear First Name". How can I do that in the HTML template? I'm still figure all this out and haven't found a way to access just first name. Thanks for any help or guidance.

Melissa