Have you identified the JSFF ot TSF for which you are going to do customisation.
if not try to identify the fragment with oracle composer..
And here is the steps on how to identify the ear.For Eg:- If i want to customise Items under Product Management Menu,
..//oracleoutsourcing.com/productManagement/faces/ItemDashboard.so from the link the appname will be productManagement.In the console,
under the deployment- productmanangementapp -->
/ u01/ APPLTOP/ fusionapps/ applications/ scm/ deploy/ EarScmPim. ear
EarscmPim is the ear file need to be taken.
But i found productmanagementapp and productmanagementcommonapp .
Is it like that we should not go with commonapp.
this EAR you have to get it from your DBA.