Your question needs some clarification, what type of 3D models are you trying to make? And did you mean insert? There also needs clarification about the maths for 9 class.
If I understand your question correctly, you want to know how to make 3D models for a project for your math class.
You can make 3D models to find the surface area of prisms, cubes, cones, pyramids, or cylinders. To begin making the models you should start with a net of the figures. A net is a 2D picture of the 3D object you are making. If you were to flatten or unfold the 3D object, what would the sides (faces) look like?
For example, a cube. What is the shape of each side (also known as the face)? It's a square. How many sides (faces) does a cube have? It has 6 sides. So you draw the six faces, in this case, squares the exact same size as if you were unfolding the cube. All the faces are attached as if wrapping a present.
An attached link will give you visuals for the nets.