You are welcome. the ?: looks confusing at first glance but it is very simple. Type a condition then put a question mark. Then type the result if true, put a colon : and then what the result is if false.
So to test it out if you have a global variable called SCORE and a textbox, choose the action set text and type:
Score < 200 ? "Good" : "Great"
If score is less than 200 the textbox will say good. 200 or more and the texboxt will say great.
Description from elsewhere:
?: is a conditional operator, which allows you to test conditions in expressions. This is especially useful when used with the comparison operators and logical operators. It takes the form condition ? result_if_true : result_if_false
e.g. health < 0 | score < 0 ? "Game over!" : "Keep going!".
The condition counts as true if it is non-zero, and false if it is zero.