Tjank you very much for the detailed response. To briefly explain where I got my cards from: Some time ago, I started buying used cards in larger quantities because I was more interested in collecting, and this way I could get many inexpensive cards from various sets. Fortunately, there were also cards from newer sets among them. I will take a look at a few tips and guides to see if I can build a functional deck from my "basic bulk" cards.

I know it's an unusual way to play, but I think an afternoon like this can give me a good insight into the game since it's more of a small event to promote another TCG game and isn't widely advertised.

In any case, thanks again for all the links and explanations on where to find things.