You got the symbols significations right and you can indeed place the right stack onto the left card as it accepts diamonds and heart cards, on the other hand, the second card of the right stack accepts Spades, Clubs and Diamonds but as the card you want to place only accepts Diamonds and Hearts (and those are the two you already have) you cant put it there because you wont be able to put the final club card you would need there.
I hope I'm clear