  A simple collision model is employed to introduce elementary concepts of open
system dynamics of quantum systems. In particular, within the framework of
collision models we introduce the quantum analogue of thermalization process
called quantum homogenization and simulate quantum decoherence processes. These
dynamics are driven by partial swaps and controlled unitary collisions,
respectively. We show that collision models can be used to prepare multipartite
entangled states. Partial swap dynamics generates W-type of entanglement
saturating the CKW inequalities, whereas the decoherence collision models
creates GHZ-type of entangled states. The considered evolution of a system in a
sequence of collisions is described by a discrete semigroup E_1,...,E_n.
Interpolating this discrete points within the set of quantum channels we derive
for both processes the corresponding Lindblad master equations. In particular,
we argue that collision models can be used as simulators of arbitrary Markovian
dynamics, however, the inverse is not true.
