Mixing colours when using colour schemes

Hi

What's the best way to (or how do you) mix colours when you're using colour schemes from the colour wheel? I did read about the Mixer Brush Tool, but I didn't understand the explanation on how you use it. I learnt about the colour schemes at college and, most recently, during my first semester at university. I'm currently experimenting with a triadic scheme of orange, purple and green for a character design. I've read that it's best to mix, shade and tint these colours to make your palette. How should I do this?

Thanks