The first command is simple.
It says herobrine entered the game.
You can always change what the command blocks say.

The second command is very odd. It teleports the player outside the world!
How cool is that!

The third command is the most simple.

All it does is /kill @e
E stands for entity.
Entity means players mobs paintings dropped
items. So I recommend having a backup of the world before you do this command.

The fourth command will trick the
player into killing themself. (It is hard to explain what it does)

The Fifth command, you will need to find out what
that does.

The Sixth command gives you a diamond sword with sharpness 10000.
Have fun killing noobs!

This is my first schematic so don't get mad if it is not the best.

If you enjoyed this please leave a diamond favourite and subscribe!

I will add more to this command if you want me to.