Blank canvases are scary. Anyone that has stood in front of one will know this. The stress that you can feel sometimes is crazy. You worry about ruining that perfect white flat surface. You don't want to mess it up. What if you make a mistake? What a waste!
Then you have to think about what you are actually going to paint. How do you decide? How do you pick one idea out of a million that are in your head?
Its a struggle.
The easiest way to get over this overwhelming fear is to just do it. Pick a colour (or three) and cover up all the white. Just slap it on. It doesn't matter how just cover it up.
There you go... the white is gone. The canvas has been messed up and now it doesn't matter what you do next.
Even now, after painting pretty much my whole life I still have that fear and anxiety when starting a new piece. Even when I know exactly what I need to do, I procrastinate starting because I worry that I will ruin it. But as soon as I cover the surface with paint the feeling disappears and I can focus on getting the work done.