Porto is a fast-playing, competitive tile-laying game driven by card play. On your turn, you either draw cards or build floors. If you draw cards, the total value of the drawn cards cannot exceed 3. (Cards have values between 1 and 3.)
If you build floors, you MUST play two cards from your hand. The number of one of the cards determines exactly how many floors you will build, and the color of the other card determines the color of those same floors. Thus, with only three cards in hand, you have six different possibilities for building; with more cards, your options increase even more! Building gives you the possibility of scoring points but also opens new possibilities for your opponents because buildings do not belong to any player. You might start a building that can be completed by other players, and it is this risk management that makes Porto a very interactive game in which paying attention to the moves of your opponents is crucial.