Call script in another script

Hi Experts,

My requirement is to fill a field on loading of my embedded component and pass that field to outport of embedded component.

1) I am trying to write script for filling field in Event-AfterLoding.absl as it read only script. I have decided to write that on custom button script. Now my       question is how can i call my custom button script in Event-AfterLoding.absl

                                                                 Or

   Is there any way to full-fill this requirement.

2) What is the purpose of Local event and PortTypePackagepath in outport. Below is the image for reference.

Thanks,

Quddus.