Hi,
Sysytem will create the central person automatically, in the backend. In general terms we can not create the central person in SAP HR.
If system will not generate the CP automatically then execute the report: RPU46CX_CENTRAL_PERSON_ONLINE
In addition to above, You can also create central person using the report program HRALXSYNC via SE38 transaction. This report enables the user to create CP objects for Employees if in case they are missing or not created. Try it out.
Go through the documentation of this program in SE38 transaction itself, you will get a good idea about the functionality of this program.
Regards,
Venkat Polisetty