Actually you can upload a header/logo just like normal on the left side, and have it clickable.
This theme (and most Genesis themes) actually use the WordPress uploader to upload logos. So when you upload a logo, it may appear to be just the image, but there is a hyperlink present as well….you would need to make sure it is set to the size of your logo.
Take a look at this popular tutorial for uploading logos in Genesis – http://www.carriedils.com/add-logo-genesis-theme/