We discuss MSSM model building in the setup of heterotic string theories.
To this end, we describe orbifolds and their resolutions into smooth
Calabi-Yau manifolds. We then explain how models on these compactification
spaces can be matched to one another by using two different techniques.
The first approach is to study the underlying gauged linear sigma models
and the second approach is to study the anomalies in both setups.
