a spell at its most basic is an act of pure will. largely using mental techniques, the caster raises, shapes and sends energy using meditation, visualization, ritualized gestures and voice/incantation.
material objects (materia) enter the picture to help the caster shape the energy, give the energy a foothold in the material plane, contain the energy for a later date and to act as a magnet for the concepts the energy is programmed with. in all cases the energy is raised then flowed into the materials. its a bit like the materials act like a vessel for the spell energy. the materials are not the spell, but they contain the spell, and help to shape it.