Neutron scattering is one of the most powerful and versatile experimental technique used to investigate the structure and dynamics of condensed matter at the atomic scale up to the hundreds of nanometers, complementary to other structural probes, such as those using photons (from visible light to synchrotron X-rays) or electrons (microscopy and diffraction), as well as to standard laboratory measurements. Fields of research covered by neutron scattering extend to a wide range of sciences such as condensed matter physics, materials science, chemistry, polymer science, biology, engineering, geology, etc. The importance of neutrons is given by their unique properties; penetrating and uncharged, thus penetrating deeply in the matter, they have a magnetic moment, wavelengths and energies similar to inter-atomic distances and lattice vibrations in condensed matter, respectively. Together with synchrotrons, neutron facilities are considered the most useful microscopic probes of matter available to all the international users communities. This review is aimed to present a general overview of neutron scattering theory and techniques related to the multicomponent molecular assemblies studies. These techniques will be detailed presenting specific instruments currently available to the users community at the Institut Laue Langevin in Grenoble (France), the most intense neutron research reactor in the world.