I wanted to use one hand with black marker and then the same hand but with blue marker. But it changes for all my elements in the video. Is it impossible to change hands for every element?
You can click the hand icon at the top of the videoscribe work area to change the hand for the whole project.
You can click the "drawing hand" tab in the properties menu of an individual element, to change the hand for that individual element.
-Mike (videoscribe user)
As Mike said each element you add to the timeline has a properties screen and there is a hand tab on that. This would overwrite the default option you have for the scribe if set.