The best way to learn 3D primitives is to start with hands-on practice in beginner-friendly software (like Blender or Tinkercad) and break real objects into basic shapes (cubes, spheres, cylinders).
This approach connects abstract primitives to tangible items—e.g., a cube for a book or a cylinder for a bottle—helping you grasp how simple forms combine into complex models. It’s widely used by hobbyists designing basic props or beginners learning 3D fundamentals.
For new learners, try a daily 10-minute exercise: pick a small household item (like a pencil holder) and recreate it using only primitives. This builds foundational skills without feeling overwhelming.