(Extraordinary is an adjective meaning unusual, remarkable, amazing, or outstanding.) "The acrobats performed extraordinary feats for the crowd." "The workers did an extraordinary job in repairing the gas leak." "The school board took the extraordinary step of firing all of the school principals."
So- you are asking when to use 'when' in a sentence. When you are asking how to use when in a question, you are already using when in a sentence, because a question actually is a sentence. I like to use when in a sentence whenever I like.