I would like to make a card game like Gwent or Hearthstone in UE4. How could I do a game like that? I would be glad if someone would give a link to some tutorial/tutorials 
It’s unlikely there is a A-Z tutorial on how to make a complete game, even for something that is no longer niche. If I were you I’d try breaking the project into small bits and try to figure out how they work.
You will want to focus on both widgets and widget components. These will be the core of visualisation. Also, don’t forget to have a look at Stainless/Wizards’ Magic: The Gathering for inspiration.