How to Find Unknown Family with MyHeritage DNA

Have you taken a DNA-test to find an unknown parent or grandparent? Or have a DNA-test discovered a big family secret, like dad not being dad? Which family members can you expect to find with a DNA-test? How can you find dad with a DNA-test with no clue on who he is? With personal examples from my own DNA-journey I´ll give you inspiration on what's possible and not.