The most basic purpose of using Program/Simulate is to control channels. Use this method to create a desired look for later record into a preset or palette.
To alter intensity for the selected channel(s), click and drag the Intensity slider in the Programmer or type the numeric intensity value in the provided field next to the slider.
The selected channel(s) will graphically indicate the change in intensity value in the Plan workspace of the Program/Simulate view, the Editor Spreadsheet, etc. Depending on the set user preferences, you may be required to zoom (press (Ctrl) + mouse scroll) to see the represented numeric value listed next to the channel.