  This review introduces Markov Chain Monte Carlo simulations in causal set
theory, with a focus on the study of the 2d orders. It will first introduce the
Benincasa-Dowker action on causal sets, and cover some musings on the
philosophy of computer simulations. And then proceed to review results from the
study of the 2d orders, first their general phase transition and scaling
behavior and then results on defining a wave function of the universe using
these orders and on coupling the 2d orders to an Ising like model. Including
matter in this type shows a strong coupling between matter and geometry, that
leads to new phase transitions. However, while the matter does induce a new
phase transition, it does not change the order of the phase transition of
geometry.
