Many spells and magical creatures you play will 'damage' your opponent, which means your opponent has to discard cards from his or her deck.
You win the game when your opponent's deck runs out of cards.
First you should have a deck made and ready. Here are the rules for your deck:
Before You Play:
The first person draws a card from their deck and puts it in their hand. From here they have 2 actions or "things they can do." To play cards it takes an action (except for Adventures and Characters, they need 2 actions to be played). The card type is always on the bottom of the picture or to the left of it at the top. With an action, you may do one of a number of things:
To play a card, they must first play some lesson cards. Lesson cards provide power to play cards. On most of the cards in a corner is a symbol and a number on top of that symbol. This bascially means that to play that card (use it), you must have that number of lesson cards in play and on the table. The symbol means that at least one of those lesson cards MUST be that lesson type. If there is nothing like this on one of your cards, then you don't need lessons to play it (it still takes up an action though). These cards usually need 2 actions to be played.

Inside the red box, you can see a 6 and a blue heart. This means that you need 6 lesson cards in play and 1 of those has to be a Lesson card with a blue heart. After you use up both of your actions, then your opponent goes and draws his card. He also has 2 actions and may use them as he wishes. If he does damage to you, it takes it away from your deck. For instance "2 damage" is 2 cards taken from your deck to your discard pile.
Certain things happen when you play cards.
Spell cards: Takes 1 action to play (if you have the right amount of lessons). Read whats in the box and it'll tell you what to do. Once you play a spell card and do what it says to do, then you put it in the discard pile.
Creature cards: Takes 1 action to play (if you have the right amount of lessons). After you play a creature it stays in play for the rest of the game until your opponent gets rid of it. To get rid of creatures, you must play a spell card that says "To -- damage to your opponent or to a creature of your choice." This will take away a certain number of health from a creature card. If it runs out of health, it must be put in the discard pile. Creature cards constantly do damage to your opponent. In a box you can see the damage it does each turn and its health. Damage each turn is what it takes away from your opponents deck each turn. You take away the damage right after your opponent draws his card for his turn. Sometimes writing will appear over the box, soemtimes you must discard some lessons to play it. This MUST be fulfilled to play it. You may have as many in at a time as you wish.
Item cards: Takes 1 action to play (if you have the right amount of lessons). After you play an item you do what it says and then is discarded. But sometime it might say to keep it in play. Sometimes they will have a "provides" box with some symbols in it. You keep these in play. They provide that number of lessons.
Character cards: Takes 2 actions to play. Once you play one, it stays in play. You can use it's power whenever you want, unless it says "once per game." However, for another 2 actions, you can put it back in your hand and then if you were to play it again, you could use that power once again. Sometimes they will have a "provides" box with some symbols in it. You keep these in play. They provide that number of lessons.
Lesson cards: Takes 1 aciton to play. Once you play it, it stays in play forever. If you or your opponent play a card that makes you discard one of your lessons, you must discard it. You need these to play other cards.
Adventure cards: Takes 2 actions to play. Once in play, they stay in play until your opponent "solves" it. Under "effect" it tells you what it does. It does this until it is put in the discard pile. If your opponent can do this, then he also gets the award listed on the card.
Match cards: Takes 1 action to play (if you have the right amount of lessons). Look under "to win." It tells you what you must do to win. But be careful, your opponent can win it too! This card stays in play until someone wins. Once someone wins, then they get the award listed on the card. Only one match card can be in play at a time.
Location cards: Takes 1 action to play (if you have the right amount of lessons). Whatever it says, applys to both people. If you play another one, the old one is discarded.
Some cards have some words writen on it you might want to know about.
Uniqueness: On Character cards, Creature cards, Location cards, and some Item cards, there might be the word unique written on it. This means that only one of them (the card, not the card type) can be in play at one time. If your starting Characters are the same, this does not mean anything though.
Keywords: Keywords are usually on Character and Creature cards. They can be used so you can make a deck "all gryffindor" or somehting of the likes. It's mostly used for as something for fun. However, sometimes cards call for you to "discard all book cards" or something like that.