1) You put the bar magnet somewehere in the carrousel (for example at the edge if you want the circumference of the carrousel to represent an electron orbit). The magnetic field caused by this magnet at the center of the carrousel (that you measure with the magnetometer) is the dipole contribution to the hyperfine field.
2) Now you put the electrically charged ball on the carrousel (again for example at the edge) and make the carrousel spin. The magnetic field generated by the ball in the center of the carrousel is the orbital contribution to the hyperfine field.
3)Now you put the child on the carrousel and give it the choice to sit anywhere he/she wants. Being a child, it will move all over the carrousel. When it goes to a horse at the center, there will be a Fermi contact contribution to the hyperfine field.