Kranzle pressure washer advice

[Hereward]

I have a powerful Kranzle pressure washer and am after the Do's and Don't's before I unleash it on my cars and potentially damage one.

I assume the golden rules are don't aim it square-on to the bodywork and don't hold it too close? But how does one know if it's too close? Any tips/advice appreciated before I destroy my paintwork, thank you.