There are many types of cards, but the main cards are the character cards. They have a photo of the character and what kind of power he has. Also listed are instructions on how to use the cards.
Your best source of information is your kids. Sit down and play with them. I’m sure they would be happy to have you play with them. Kids want their parent's attention, and they want to show mom and dad how knowledgeable they are. There is a vast world of knowledge in the Pokemon realm.