You can learn more about the Product Canvas by reading the following articles:
The Product Canvas provides an overview of the canvas, explains its sections, its relationship to the Business Model Canvas, and electronic canvas tools. It also provides links to posts that discuss its techniques in more detail.
The Product Canvas Creation Workshop provides useful tips on how to create your initial product canvas.
New Product Development with Lean Startup and Scrum shows the role of the Product Canvas in a lean innovation process.