TexDraw doesn't actually draw anything onto the model I'm quite a noob with blender so it probably has something to do with something I haven't ticked, so I'll give as much information as possible.

So I've built a very basic building to later export it into a game, I have made the UV and Unwrapped it, but when I'm trying to draw a texture into it by using Tex Draw, the texture doesn't actually get applied:


I don't know if it has something to do with the shading or what to be honest, here comes my shading settings too:


Here are the settings for the brush too


If there's anything I am missing please do let me know and I'll answer as soon as possible, I just really want to start with the texturing as I've been working hard (as hard as you can when you are a beginner really) in this model, thanks :D
Here's the .blend file:
You have created a Texture Mask, and as it is completely black you can't paint anything, you need to remove it:

Also maybe lower the stencil Opacity:

And make sure the normals are correctly flipped (ShiftN):