There should be mission instructions in the black drop. You have to turn off other tasks first, and then press M and L to view the small map of Black Drop, and you can find the mission location. There is a room in the dungeon with a machine in it. If you do this, the scroll will appear.

I'll tell you the order of the machines. Press the button on the left until it can no longer be pressed, then press the button on the right, and so on. You can copy the dictionary and take the scroll.