So, if you've already had experience with programming, you probably know what a variable is.
A variable is something that holds a value, it can be a number, a word, a boolean value, anything!
So, we are gonna need a variable.
Go to the "Data" scripts tab, and click "Make a Variable".
Go ahead and name it "Score"
So, when the game starts, we want the score to be preset to 0.
Drag the "Set Score to 0" block below the green flag.
Now, you want the score to change.
So, in the mouse, drag "Change score by 1" block, under "When receive message1" blog.
You have score now.