scoreboard_add()
Syntax
scoreboard_add(objective)
scoreboard_add(objective, criterion)
Adds a new objective to scoreboard. If criterion is not specified, assumes
'dummy'. Returns true if the objective was created, or null if an
objective with the specified name already exists.
Throws unknown_criterion if criterion doesn’t exist.
scoreboard_add('counter')
scoreboard_add('lvl','level')