Hello Shaila
Please check the guides in http://scn.sap.com/docs/DOC-7858#section2
Especially this one:
How To... Master Data Governance for Material Extend MDG-M User Interface
Please bear in mind that the IMG activitiy you mentioned (Edit UI configurations) is only relevant for the generic UI USMD_ENTITY_VALUE2, not for the EhP6 (and later) UIs for material/supplier/customer.
Best regards, Ingo Bruß