  We review the model building aspects for keV sterile neutrinos as Dark Matter
candidates. After giving a brief discussion of some cosmological and
astrophysical aspects, we first discuss the currently known neutrino data and
observables. We then explain the purpose and goal of neutrino model building,
and review some generic methods used. Afterwards certain aspects specific for
keV neutrino model building are discussed, before reviewing the bulk of models
in the literature. We try to keep the discussion on a pedagogical level, while
nevertheless pointing out some finer details where necessary and useful.
Ideally, this review should enable a grad student or an interested colleague
from cosmology or astrophysics with some prior experience to start working on
the field.
