Help getting JavaScript Editor to Open

I am brand new to all of this and I am trying to write a simple script to export the data in a PDF to an XML file.

When trying to create a new script all I get is a box that pops up saying GoTo then once I click this it asks for a Line Number and that's as far as it goes. I have read that this should open the JavaScript editor and it does not.

Any help would be appreciated.  Thank you.