How exactly does the Minecraft / scoreboard command work?

Hi, I've been playing Minecraft for over 7 years now, but I've never used the / scoreboard command. I'm currently playing on my own server with a lot of other people, and it just happens that someone quarrels or something, so I would like to stipulate that if you did something bad 3 times you get a penalty so that everything is there I would have liked to have the number of "penalty points" displayed on the right of the screen (I would like to set this manually) that works with the / scoreboard command, right?

If so, could you write me how this order works?

I'm not familiar with the command myself, but I found this tutorial:

Just take "dummy" as the objective, then it only changes manually

Unfortunately I don't have a Mc at the moment, but I'll try it from memory.

/ scoreboard objectives add BadDates dummy "BadDates"

/ scoreboard objectives setdisplay sidebar

/ scoreboard players set @p BadDates 1

/ scoreboard objectives add penalty point dummy

/ scoreboard objectives setdisplay sidebar

/ scoreboard players add penalty point 1