Need help with Lego microgame tutorial, "customize game" 6/11, cant add action

In the Lego microgame, in the part “Customize your game” step 6/11

There is no plus in the “specific actions” menu (I have linked a picture)

Is there some way to get the plus to show?

Is there some other way to “add an action” ?

https://imgshare.io/image/whereistheplus.p8bb6t

I got the answer.

Change the number from 0 to 1 in specific actions, size, and that will make it work.

There is no size count in Specific Actions. How can I change the number to 1?