Making 3D shapes from paper involves deciding on a shape, cutting the paper to include all facets of the shape and gluing the edges together. Simple 3D figures include pyramids, cubes, cones and triangular prisms.
When making a 3D shape out of paper, one has to consider the number of sides the desired figure has. For example, a cube has six sides and a pyramid has four. To make gluing easier, each side needs a small flap to glue it to the adjacent side.
Perhaps the easiest 3D figure to make is a cone. The shape to cut out is a wide triangle, with one side curved. The paper then needs to be curled around itself, with the outer edge glued to the cone. To make the bottom of the cone, one needs to cut out a circle with a diameter the size of the cone's circular opening, making sure to add two or three flaps for gluing. One then folds the flaps up, slides them inside the cone's opening and glues them securely to the sides, making sure the bottom fits snugly against the opening.
A cube is another simple project. The shape to cut out is in the form of a cross with four equal squares making up the long piece and three for the cross piece. One folds the paper along the lines for the squares and glues the sides in with the flaps.