The Mackin Score Board is easy to use. The on/off switch is inside on the wall to the left of the scoring table. This video has details on how to use the scoreboard.
Scorekeeping in baseball is a bit more involved than other sports and has a bit more of a learning curve. To the right are 4 videos that do a good job of explaining how to keep score in detail. You can view the full playlist on youtube here https://www.youtube.com/playlist?list=PLeGye43uX0gIPfsT-NNVpGLRSFrje4T23. You can find more videos on scorekeeping below
Pitch count League Ages - Pitch count regulation (Click Here)
|50 pitches per day
|75 pitches per day
|85 pitches per day
|95 pitches per day
|105 pitches per day
|Exception: if a pitcher reaches the limit imposed in regulation VT (c) for his/her league age while facing.
Scorekeeping - Short 4 minute video
Scorekeeping - Longer more detailed vidoes