creative writing - How much description is necessary?

I have trouble imagining things. With me everything is blurred, as if I were almost blind. That's why I find it hard to describe things. For example, the protagonists enter a castle. I have a very rough idea of what the castle looks like. But when it becomes more precise, it becomes much more difficult. I couldn't say exactly how the rooms are decorated, only that they are decorated. I'm always worried that I won't describe enough and the readers can' t get a picture of the setting. How much description is necessary and when is it too little?