First, there is no right or wrong way to paint chipboard.
Second, there is no right or wrong medium to use on it.
Third, you cannot fail because there is no gold standard.
Armed with these thoughts, you can be bold, crazy, or conservative. You can paint the smallest mural in the world, or take up a whole wall. But we will start with smallish boards just to get the hang of what to look for, what to develop. I usually start with sketching the outlines of what I can see. You might not. You might decide to ignore the textured surface altogether and impose an idea you have in your head onto it.
You can bring your own paints/inks/brushes/ pastels etc, or I will provide some. If you want to look at another example of Mini Murals, check out Jan 14th 2011 below to see what some other total novices produced.