Early in the story, Alex will give you the Dr. Kelstrup's safe code where the Neuromod fabrication plan is found. Progress a bit in the story to get the general key that gives you access to the Psychotronics section of the ship. Follow the quest marker into Psychotronics until you reach Dr. Kelstrup's room and open the safe with the code. After you built a few Neuromods, you will get an error that prevents you from building any more. This triggers the next side mission. Return back to the Neuromod Division and repair the grav shaft to reach the upper floor. From the upper floor, enter the Volunteer Quarters, proceed through the door to your left, and go inside the room behind the desk. Use the Gloo Cannon to get up there and enter the main room, where there will be a lot of enemies. Get Dr. Kelstrup's keycard from his body. Use the grav shaft to get to the upper floor again and enter the room with the keycard. Dr. Kelstrup's workstation can now be used to lift the copy protection so you can build as many Neuromods as desired.