PostworkShop now opens with a simple canvas allowing you to directly paint and draw on it without the need to load any external images. As you can see in the image below, there are no images opened: Properties+Preview pane show no image info, only the canvas size which is 800x600 pixel.

You can change the Canvas' properties in the Options/Preferences menu. 

When you are done with the canvas settings, switch to the Freehand Painting tab, as shown in the 4.0 The Freehand Painting Module tutorial. In the Settings window open the Clone Mode, Visual Guides and Canvas parts. Make sure your settings are:

  • Color Mode: Color. In this case, choosing a different clone mode does not make sense since there is no reference image or cloning source.
  • Visual Guides: Off
  • Canvas: Color. Set the color of your canvas if you haven't done it yet in the Preferences menu. 

Click the Color browser. You can choose the color you want in different ways: use the classic color-wheel, the HSV color Space or the Color Names list. Then press OK.

The canvas' color is updated to the chosen color in the viewport and in the Settings window too.
You can now start painting on it. Chose the brushes you want, their size and unleash your creativity. We have chosen to set the brushes' color to orange and to use the Ornament 02 brush family from the Creative category. 
We simply painted a few lines. 
To create a more naturalistic effect, in the Compositing view, add a Texturizer filter (from Building Blocks/Simple Styles) above the Default Layer and blend them together or, more easily, after the Bitmap Editor filter.