If matter is made up of quanta and particles, what is energy made up of?

This is a somewhat complicated problem. Energy is everywhere, but people can't see it or touch it. According to Einstein's conservation equation of mass and energy, in an isolated physical system, the total energy in the universe is a conserved quantity.

What constitutes energy is not quantum or particle as we usually understand it. Energy is just the ability of a physical system to do work for other physical systems. In our physical description, energy is divided into mechanical energy (kinetic energy and potential energy), thermal energy, electrical energy, chemical energy, radiation energy and so on. These energies are interchangeable. Every time a substance becomes hot, cold, moves, grows, makes a sound or changes in any way, it will consume energy.

When a substance has velocity, it is said that it has kinetic energy and various forms of potential energy. Kinetic energy and potential energy can also be converted to each other. For example, if you throw a stone very high, it will slow down slowly, and then kinetic energy will be converted into potential energy; However, this potential energy is not the property of the stone itself, but the property of the stone plus the earth; Once a stone reaches the apex of its trajectory, its potential energy will be converted into kinetic energy.

As for heat energy, in ancient times, people thought that heat was the expression of a substance called phlogiston. People think that this kind of substance flowing in an object is also the medium of temperature change. It was not until modern times that people began to understand that heat is a kind of emergent nature of the collective movement of material particles.

Matter is indeed composed of quantum and particle, but quantum and particle are actually just an excitation mode of basic quantum field. In fact, the matter we can perceive is excited by a large number of interacting fields, so it involves a lot of mechanical energy, chemical energy, thermal energy and so on.

The great discovery of modern physics that "matter is energy" can also be understood as that matter is only a manifestation of energy, so a part of energy (material part) is composed of quanta and particles. Matter, energy and some things that we can't find now make up our world.