The support page says:
Is there a prebuilt image for DRAWS?
The short answer is Yes.
Starting with delivery of the DRAWS HAT, a downloadable image will be available to run the DRAWS workstation. It will contain the current version of Raspbian (Stretch) including preloaded DRAWS HAT driver and a selection of applications that have been compiled for and tested on the DRAWS platform.
I now have my DRAWS HAT delivered, where do I find this downloadable image?