It is not possible to create an "Input Field invisible" for a defined variable as described in [http://www.ooowiki.de/EingabeFeld#Schritt_2:_Eingabefelder_definieren] (in german only, sorry).
Therefore it is not possible to put any instructions for this variable so that the user can fill in the variable with suitable terms.
marked as enhancement request
Created attachment 107620 [details]
The problem step-by-step
All the steps are reported this file.
(In reply to Pit Zaclade from comment #0)
> Therefore it is not possible to put any instructions for this variable so
> that the user can fill in the variable with suitable terms.
According to help, it is not possible to make input fields invisible.
If the actual problem for you is to put instructions into an input field, then you do not need to make it invisible. You can enter instructions in the input field.
If that is not what you wanted, then please explain again. I will change status to NEEDINFO
(In reply to Alexandre Falcão from comment #2)
> All the steps are reported this file.
Thanks for the detailed report. Your procedure is correct. But I could not reproduce the problem using LO 184.108.40.206