1. Plot your chart by selecting the symbols and data fields of your choice.

2. Select "Show Custom Formulas" in the bottom left of the screen. This will allow you to create your custom formulae.

3.  Click "Add Function" to create a custom function.

4.  Using the mathematical symbols with the plotted data series you can construct your custom formula.

5. Click "Save" and "Add" to plot your custom function on your chart.

Tip - Use the   icon to hide the series that you do not want to see plotted on your chart.