Starting programming in smalltalk problem to mix two colors

Hello everybody i am starting programming in smalltalk. I hav already posted on the forum and I have had some answers to solve a part of my problem but I still cannot do what I want to do.
Here is what I want to do, I would like to mix two colors that I have selected in two different HSVA selectors and get the result in a square morph or something like that but I don't manage to mix the two colors and to get the result of it into a morph. Does anyone know what to do?
Here is the code (i am using pharo):

exampleColorMixer
        "Open a window with a color mixer."

        |dialog builder|
        builder := ExampleBuilderMorph new.
        dialog := (builder newPluggableDialogWindow: 'Example Color Mixer') useDefaultOKButton.
        dialog contentMorph: (dialog newRow: {
                dialog newLabelGroup: {
                        'Color Selector 1' ->
                        ((dialog newHSVASelector: Color black
                                        help: 'This is a hue-saturation-volume-alpha selector')
                                        minHeight: 100; minWidth: 120).
                        'Color Selector 2' ->
                        ((dialog newHSVASelector: Color green
                                        help: 'This is a hue-saturation-volume-alpha selector')
                                        minHeight: 100; minWidth: 120)}.
                        dialog newVerticalSeparator.
                dialog newTitle: 'Mixed Color' for:
                        ((dialog newHSVASelector: Color cyan
                                        help: 'This is a mixed color from the two other colors.')
                                        minHeight: 184; minWidth: 184)});
                model: nil.
        builder openModal: dialog

Thanks for the future responses.