To add the sides, squeeze icing on lower edge of one side piece and side edge of the front piece. Align pieces at a right angle, making sure they are as tight as possible. Repeat with the other side. To add the back: squeeze icing on the bottom and side edges of the back piece; position with the other assembled pieces. For add stability, squeeze icing along the inside edge of all pieces and corners. To assemble the roof: working with one side at a time, squeeze icing on the upper edge of the slant of the front and b back pieces on one side. Also squeeze icing on the adjoining side piece. Carefully place roof piece on the slants so that the roof's peak is even with the points of the front and back (There should be an overhand of 1 cm). Repeat with other side of the roof. To decorate: add a chimney if desired. Decorate the house with remaining icing, candies and cookies of your choice.