The Atacama Large Millimeter/Submillimeter Array (ALMA) is the largest radio telescope currently under construction by a world-wide collaboration. The first antennas (the total will be 54 12m antennas and 12 7m antennas) are being commissioned to become part of the interferometer at a high site (5000m) in Chile. The ALMA Software (~ 70% completed) is in daily use and was developed as an end-to-end system including proposal preparation, dynamic scheduling, instrument control, data archiving, automatic and manual data processing, and support for operations. The management lessons learned will be explained. Aspects described will go from requirements analysis to the use of a development framework: ALMA Common Software (ACS) in our case. The process used to provide regular releases will be outlined, including temporary cross-subsystem teams. The importance of integrated regression tests will be stressed, but also the need to validate the system with users. Among the project management tools risk analysis, earned value measures and tracking of requirements completion will be presented. Monitoring progress with reviews and the possible impact on completion dates will also be discussed.