This is template for Alex Osterwilder's Business Model Canvas
http://www.businessmodelgeneration.com/canvas
it is a tool for quick and fairly easy clarification of business models.
Original canvas is good for showing and analyzing existing businesses, however for startups, I found Ash Maurya's one, a little bit more convenient: http://www.ashmaurya.com/2010/08/businessmodelcanvas/
Idea is that you will fork this, use it to analyze your ideas. Make versions old fashion way, by copying so you can display your idea evolution more easily.
For start there are two templates, canvas.html that coresponds to Alex O and Steve Blank materials, and startup.html which is more along the lines what Ash Maurya is advising. Use this as a starting point for your analyses.
The way you use them is to copy template to file named model-*, that way git will not pick it up and you can get updates from this repo.
So if you want to start a startup template, you would do
cp startup.html model-brightidea.html
then work on model-brightidea.html and you can update repo without having anything overwrite your stuff.
I have to mention existing online tools as well, however I do believe this and paper to be superior.
Here is one from Ash Maurya's Spark59: http://leancanvas.com/
And there is one promoted by Steve Blank: https://www.leanlaunchlab.com/
Zeljko Dakic