If you're reading this, It means you're interested in using the Minecraft Scoreboard commands!

First off commands/cheats must be enabled for the player doing this

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Step 1:
Next in the chat or console follow these steps to ADD AN OBJECTIVE:

/scoreboard objectives add [name] [Criteria] [Display Name]

-Criteria is somethink like (health, death counts or player kill or even more)

-Insert "deathCount" in Criteria for total deaths display
-Insert "playerKillCount" in Criteria for Player PVP kills display
-Insert "totalKillCount" in Criteria for Player PVP and Mob Kills display
-Insert "health" in Criteria for Player health count display

-You can name the objective whatever you would want it called in the [name] section
-You can also do the same to the display name in the [DisplayName] section

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Step 2:
After you've added all of your objectives next this is how to DISPLAY OBJECTIVES:

/scoreboard objectives setdisplay [slot] [objective]

-Slot is wheather you want your display to show in (The player name display, over player heads, or on the right hand side of your screen) You can have all 3 displays on one objective if you would like.

-Insert "list" in the [slot] section to have the objective displayed in the TAB player list
-Insert "sidebar" in the [slot] section to have the objective displayed on the right hand side of the screen
-Insert "belowName" in the [slot section to have the objective displayed below the players name in game

-Insert whatever you wanted displayed, named in your objective(s) from Step 1 in the [objective] section

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IF YOU MADE A MISTAKE AND ACCIDENTLY PRESSED ENTER:

-If it didn't work chances are you made a mistake when you were typing, you're going to need to go back and see what went wrong!

NEW COMMAND:

/scoreboard objectives list

-this will tell you the name of the objectives you've added and what they display
-Once you have found out what isn't being displayed you're going to have to REMOVE it with a command

NEW COMMAND:

/scoreboard objectives remove [name]

-Insert the name of the objective that is displaying the non-functioning display
-Once removed you don't have to worry about it any more

If you made the mistake go back to step one and type more carefully!!