How do I save instance variables to Storage?

I have a card game with 50 cards. Each card is an instance of an object. Each instance has two variables: card value and if the card has been turned.
Im trying to save the game state to storage with
Pick all instances of Card
I’ve tried to write with:
Write Card.Variable(CardNumber) in “Card.CardNumber” of Storage “Autosave”
But it writes only the data of the first object instance to the storage.

I know I have to define the object instance for the Write somehow but how is it done?

If you want to save all of them, use a “for each object” loop.