SAP has modules for almost all business process involved in any industry ranging from Procurment of raw materials (SAP MM) to Sales(SAP SD) of finished product with Finance integrated between all (SAP FICO).
These are functional modules that cater to best practises in which a business process should be performed.
Then there are Technical modules of SAP ranging from administration of SAP Software ( SAP BASIS) to development of customised software in SAP ecosystem ( SAP ABAP , SAP HANA, SAP Fiori )
If somebody is starting from scratch without any bias /inclination towards or no prior knowledge or opportunity in particular module, I would suggest to pick SAP evergreen programming language ABAP and any one functional module SAP MM or SAP SD.
Since SAP is essentially a business software one needs to have know business side of things (Functional module) and being CSE grad one can easily pickup ABAP.
Aim towards becoming techno functional.