The simple slider changes the maximum value the parameter can attain during the brush stroke.
You can change the maximum value of the slider manually by clicking on the value and typing a number or by dragging vertically.
Note : Opacity can't be set to more than 100%
Click on the arrow next to the parameter name to unfold an extended version of the slider.
In the extended version you can change both minimum and maximum values.
The minimum value is the lowest value the parameter can have during the brush stroke.
In this example, the shape will never be smaller than 7 pixels when the pressure is low and never larger than 23 pixels when you press harder on the stylus.
You can change both minimum and maximum values at the same time by moving the small block above the slider.
This will modify the two values while keeping their relative difference.
Setting the same value to minimum and maximum will disable the controller and the parameter will always have the same value.
In the image on the left, the size will not change over the pressure of the stylus.