Since I don’t know much about writing shaders yet, I would rather start with the standard, see how it works and modify it, instead of starting from scratch. So, can anyone tell me where I can find the vertex/fragment shader sources?
You can just create a new shader and open it up in Visual Studio to see the source for it, as well as edit it and create your own. If you’re just getting into shaders I’d recommend these two websites for some great intro and tutorial material: