I need help with character customization

I want to be able to let a player customize their character. (a cube) to be able to change the color, and apply brushes like in Photoshop. For an example I want to be able to take the circular stamp and stamp on red dots, then select the star and make blue stars etc. I use c#. I’m not sure where to start.

The stamp concept is easy to implement… create the prefab of the object… then on the click event instantiate the stamp on that position…

to change the color:
gameObject.renderer.material.color = Color.white;