I am quite new to C2 myself, but I am currently making a simplistic game that uses a timer as a score.
The way you would do it however is using a variable:
Define a variable and call it Score and default value to 0
In your layout add a text string and call it ScoreDisplay with default text "0"
Whenever an action increases the score, in your event you would go System > Add to (under variables section) and then add whatever score value you want to the variable.
System > Every tick set the text value of ScoreDisplay to your variable.
This should get the job done.