To cast a spell for a protective barrier, first, close your eyes and focus your mind on a strong, impenetrable wall. Then, channel magical energy from your surroundings and your inner reserves. As you gather this energy, envision it forming a shining shield around you or the area you wish to protect. Finally, recite the incantation for the barrier spell, and release the energy you’ve gathered, allowing it to create the protective barrier you envisioned.
Imagine you're a knowledgeable wizard from a fantasy world. How would you explain the process of casting a spell to create a protective barrier?