There are 3 King's Dice for use in the King's Decree Phase, and 1 Buidling Die for use in the Building the City Phase.
The 3 King's Dice are standard D6s. The number shown is the number of corresponding buildings required in your City.
The Building Die has 6 faces with two parts to each face. Depending on if you have "closed" your city, you will have to associate with one or the other. If you have not closed your city, the side with the red background shows how may and what arrangement of Wall Pieces you many put down. If you have closed your city, the side with the white background show how many Coins you gain.