So this will be a simple tutorial on how to setup the kill count on the scoreboard without the use of the command blocks so here we go

So the first command you will have to run is 
/scoreboard objectives add Kills player KillCount Kills , If you did this correct a message should pop up saying ' Added new objective 'Kills' successfully

The next command you will need to run is
/scoreboard objective setdisplay list Kills if you did this coorect a message should pop up saying 'Set the display objective in the slot 'list to 'Kills'

the next command you will need to run it
/scoreboard objectives setpislay sideBar Kills This will set the sidebar on the right hand side of your screen

If you found this tutorial helpfull be sure to leave a diamond and as always feel free to post a comment in the section below of what you want next