How to make a „Check All“ checkbox?

I have a series of checkboxes. Right now, I have to check them off all individually. but I would like a way to mark them all as checked (for this record), with a single checkbox, positioned above the portal.

Mark all as checked.png

I was able to find a script but I don’t know how to create a script. It won’t let me just paste in the text.

Set Field [ table::field ; If ( IsEmpty ( TABLE::Field ) ; ValueListItems ( Get ( FileName ) ; „ValueListName“ ) ; „“ ).