Place one full graham cracker on a cutting board. Use a serrated knife to carefully cut diagonally across the top half as shown (a gently sawing motion works best). Cut diagonally the other way so the graham cracker has a triangle shape on top. Repeat with a second graham cracker.
Cut the other two graham crackers in half so you have four graham cracker halves and two graham cracker halves with triangle shapes on top (they will support the roof).
Lay one roof support cracker in between two graham cracker halves. Pipe a line of melted white chocolate (or royal icing) down each side of the graham cracker halves.
Fold up each graham cracker half and press it again the edges of the roof support cracker. Hold for about a minute, then carefully lift up all three crackers to a standing position and insert the other roof support cracker.
You now have the four walls put together. Pipe white chocolate or frosting along the top edges of all four crackers and place the two remaining cracker halves on as a roof, piping additional white chocolate along the peak of the roof.
Let house stand for at least 10 minutes to set up, and then decorate with candy as desired.