Let me clarify some of your questions.
Understanding SAP and Its Relevance to HR
SAP is an ERP, i.e., Enterprise Resource Planning, which means SAP has developed software that caters to various functional domains in the organization like Finance, HR, Sales, Materials Management, Quality Management, CRM, etc.
SAP ERP has various modules like SAP FI/CO, SAP HCM, SAP SD, SAP MM, SAP QM, etc.
Role of HR Professionals in SAP
Since you have core HR experience, you will fit in the SAP HR module. Again, in this, you can be a Functional or Technical Consultant.
Types of Consultants in SAP HR
- **Functional Consultant**: You will be responsible for configuring the various sub-modules of HR like OM (Organizational Management), PA (Personnel Administration), Time Management, Payroll, etc. Here, there will be no coding.
- **Technical Consultant**: These are the programmers who work on the ABAP language on which SAP is developed. They are responsible for coding and customizing custom reports, interfaces, enhancements, etc.
Important Learning Areas in SAP HR
Regarding what important things to learn, SAP is like an ocean, so you should try to learn the module in which you have the core experience. In your case, it's SAP HR. Once you have learned and completed some implementation projects, then you could look to expand your skill sets.
Hope this answers your questions.
Best of luck!