I would like to start with some basics about local models - in fact with no level p involved - to give some examples and illustrate some phenomena. I would then like to explain what are displays, how one uses them to study deformation problems and a technical lemma that allows one to calculate universal displays. This will then be applied to calculating the universal display of Hilbert modular varieties in the case of bad reduction, and time permitting, in cases of quaternion algebras ramified at p.