What is the best way to program a CNC mill turn machine?

Mill-turning machines introduce complexity not seen in many other milling machines or lathes. Mill-turning machines often include multiple turrets with different tools, some of which can engage the part at the same time. For this reason, the most important aspects of safe and efficient mill-turn programming are 1) robust mill and lathe programming techniques, and 2) the ability to properly synchronize tool motion from multiple locations.