How does superfluids and Bose-Einstein Condensates form?

The general misconception is that the bosons in BEC and superfluids are in the same quantum state including the same spatial coordinates. This would result in stacking of each particles' wave function and unlimited reduction in volume of such a substance.

The truth is that the particles in BEC or superfluids do not necessarily crowd, but have the capability to do so when perturbed or set into flow motion. They still experience the electromagnetic repulsion between them which prevents their volume from unlimited decrease and this also serves to explain its $0$ viscosity. The internal repulsive EM forces is conservative and does not dissipate energy, rendering no internal friction which in turn renders viscosity at $0$, (there is lack of attractive forces between the particles to increase it's viscosity).

First of all, I have not directly worked on BEC or laser cooling per se, but what I am writing is my understanding after discussing this subject with a person who is directly involved in this activity. Hence if anything is wrong or inconsistent please let me know.

As rightly said by @Lagrangian that it is not required that the particles should be at same co-ordinate position. I would like to add that when we cool Bosonic atoms then the wavelength of the atoms (that means both electrons and nucleus as a whole) start to increase. After the cooling by laser cooling and then magnetic evaporation there are very few particles left inside the volume (density ~$10^{13}-10^{14}$ particles per cc). If the wavelength of the particles is large enough that the volume within wavelength contains more than 1 (appreciably more than 1) particles. The wavefunctions of these particles will try to overlap and since they are bosons they will try to go into the ground state.

This overlapping of wavefunction results in the appearance of a large density peak at the center of BEC. Though classically the particles are not at same position. However in this condition it become impossible that one can distinguish between the constituting particles of BEC. You may visualize the BEC as cloud of atoms where individuality of each atom is lost.

The large density peak is the manifestation of the maxima of wavefunction overlap. You can not say that the atoms are at same coordinate positions because they are no longer different atoms but a single wave-packet of the size of BEC.

Regards,