Like many things on the project exactly how this will work will come out of experimenting. For now we will build documentation only for the <canvas> element. This will allow us to have a working prototype to build discussions on and also be helpful for people new to working with the <canvas> element.
Please take a look through pages listed below for more details.
NOTE: It would be nice to collaborate with the Open Web project so as to not duplicate work or fragment mindshare.