Auto populate of Project and Task values on changing of DFF(contains Project and task num)

Summary:

Hi

Need a small requirement

In Supply Chain Execution > Inventory -> Create Miscellaneous, while changing any DFF value which is a LOV and also it is concatenation of (work order number-sun type -Project number - task -ledger id). Now on changing any value of DFF we need to auto populate project and task numbers ,(which are standard fields at different locations in the same page) based on the selection.

object :

Supply Chain Execution > Inventory -> Create Miscellaneous

we tried to do add Groovy script, but we could not find the objects in App Composer and also tried to edit in page composer we could not edit the field.