Hello @Stanislas_Berteloot
The first thing is that you need to know how the functions work or write (syntax) in Make.
https://www.make.com/en/help/functions/using-functions
The Make Function has a specific syntax, But in your second attached image, you’ve just written it down as like text.
While using the function or previous steps data, I strongly recommend using that data selection panel.
This is just an example of how to write that same thing using Make’s function syntax.
{{formatDate(now; "MMMM DD YYYY h:mm A")}}
Also, check this Transforming Data using Functions - Make Academy
