This is the third in the series of PlanetMag workshops. The planetary interiors group at the Max Planck Institute for Solar System Research brings their expertise of dynamo theory to you. Learn how astrophysical magnetic fields are maintained over astrophysical time scales. Learn the numerical tricks of MHD problems. Hands-on sessions with our 3D MHD spherical shell code MagIC will enable you to solve real astrophysical problems.