  In this contribution a broad overview of the methodologies of cosmological
N-body simulations and a short introduction explaining the general idea behind
such simulations is presented. After explaining how to set up the initial
conditions using a set of N particles two (diverse) techniques are presented
for evolving these particles forward in time under the influence of their
self-gravity. One technique (tree codes) is solely based upon a sophistication
of the direct particle-particle summation whereas the other method relies on
the continuous (de-)construction of arbitrarily shaped grids and is realized in
adaptive mesh refinement codes.
