I am but a tiny piece of a spirit; I belong to the alicorn named Celestia.

You have within you the spirit of one of the Elements of Harmony, it allowed me to reach you.

You can't do it alone. Have you noticed the jewels that came with the horn? The jewel representing magic, along your horn, will allow you to use the magic within your spirit in the human world. For the time being, your task is to find the other five holding the spirit that will allow them to access the other Elements.