The purpose of this lecture is to introduce the VLBI user to the practical details of mapping radio sources. I will concentrate on data processing and mapping with the AIPS (Thompson and D’Addario, 1982)-package. Other data reduction systems do exist, e.g. the Caltech-package and OLAF. These differ from AIPS mostly in the strategy for reaching the final and “best” map. It is more important to know the method and to be careful than what reduction procedure is used.