In this simulation there were actually only two flights of the 1B as part of the Apollo program. The first one was a test of the lunar module's performance outside of the atmosphere, along with a "fire in the hole" test. This was where they fired the lunar module's ascent engine without separating the bottom, simulating an emergency abort on the moon. The second mission was a test of the lunar module extraction, which is where the command module releases, turns around, and docks the nose to the fuel tank to simulate connecting the capsule to the lander.