You can use it passively and actively.
Just wear it, experience more energy - that would be the passive way. Some folks (includes me) have reported that just wearing this pendant increases their capacity to wear/use more fields than they usually can.
But that is just scratching the surface. The real magick of this Field has more to it. You can intentionally gather specific types of energy in this tag. For example, I had done a certain ritual for a deity which took 8 hours and the place was buzzing with electric blue energy. I could gather that energy in my tag so I could use it later. I also sometimes collect energy from moonlight, sometimes during rain and thunderstorms (and earthquakes though you have to be careful here), and use it later to redirect this energy for healing, upgrading vibration, manifesting outcomes, etc.
The word “Magi” or “Magus” has the clue. When doing ritualistic magick, psionic work, astral work, manifestation, etc., this is a big boon - one can easily utilize this significant source of energy to do all such workings. Or, use it for simple things like healing a pain, clearing a room, etc. by intending to redirect the energy from the tag.