Don't get too attached to your cards, because they must be expended for the sake of progress. When you mix, you take 2 cards in your hand and lose them (they return to the supply or are discarded). In exchange, you get the colour that the two colours you got rid of make. Each colour has the pigments that make it up written on the left side of the card. For example, when you mix cyan (c) and yellow (y) together, you get the colour known as Jungle (cy):

Jungle is pretty cool... but all things are temporary. Since Jungle has 1 cyan and 1 yellow pigment, you can mix it with Cyan to make Turquoise:

When you print a card, you play it from your hand to a personal space called the Play Area. This triggers instant effects on the card played. Additionally, some cards have effects that only apply while they are in the play area. Also, cards are only worth victory points in the play area.

Cards with instant (lightning-bolt) effects activate immediately. For example, Soft Cyan adds a Pale Magenta OR a Light Yellow to the hand.

Cards with continuous (infinity sign) effects are only active while they are in the play area. They are split into 3 main types:

Activated by actions
Modify actions
Win conditions

Cards that are activated by actions give you bonuses for taking certain actions. For example, while Jungle is in the play area, that player adds 1 Rank 1 card to their hand when they take the Refill action. Effects that modify actions make your actions stronger. For example, Lemon allows a player to mix twice in a turn. Finally, win condition effects unlock a new way to win the game.

Out of ink? Time to refill! When you take the refill action, you get to pick up any number of cards in your play area and put them back in your hand. This is useful because it lets you print cards again or mix with them.