Quantum numbers are the set of four parametres given to an electron attached to an atom which describe the characteristics of its movement. The Pauli exclusion principle states that no electron can have the same four quantum numbers.
Principle quantum number - corresponds to the main electron shell in which the electron resides. Can have the value n=1, 2, 3 up to 7 corresponding to shells with increasing amounts of energy
Azmuthal quantum number - corresponds to the electron subshell of the electron. Can have the number l=1, 2, 3 up to n-1
Magnetic quantum number - corresponds to the orbital of the electron, the orbital is the different orientations of the electron subshell around the atom
Spin quantum number - corresponds to the spin of the electron, can have the value 1/2 or -1/2, indicating that each orbital of an atom can only hold 2 electrons