QM for beginners is probably best described by the Bohr Approximation for the hydrogen atom. This is a toy approximation with a lot of details simplified (an thus distorted and inaccurate), but it gets some of the essentials in place. In the Bohr approximation of the hydrogen atom, we have a 2 dimensional model of the electron's orbit around a proton. This is classically akin to a satellite orbiting a planet. The difference however is the altitudes or distances that the electron is allowed to orbit only at specific altitudes. Again this Bohr atom is an approximation, there are some inaccuracies in the Bohr description, but it was good enough to approximately explain the emission spectrum of hydrogen. Bohr could not actually "see" the electrons in orbit, he had to model its behavior by guessing (making an inference) form available data.

the Approximate (and thus inaccurate, and distorted model) of the electron orbits for the hydrogen atom in the Bohr model is depicted as follows:

The orbital altitudes were thus at discrete or "quantized" levels, hence this is likely the reason quantum mechanics is called QUANTUM mechanics. The Bohr model looks innocent enough, but innocent looking results led to disturbing and spooky implications about reality and even God as scientist followed the evidence further.

Unfortunately, the rest of quantum mechanics is not so easily explained, and it requires rather brutal and tedious math and descriptions.