You must be logged on with a Sysprog type user, like Herc01, to be able to define new users. Take a look at the job in SYS2.JCLLIB(ADDUSER). You need to change the invokation parameter HLQ to the new userid, and you need to specify if the new user is a system programmer, or not. Creating a "normal", non-sysprog type user will be done with a jcl line like this
//ADDUSER EXEC ADDUSER,HLQ=GWBUSH,UTYPE=USER
whereas a sysprog type user would be defined via //ADDUSER EXEC ADDUSER,HLQ=VOLKER,UTYPE=SYSP
There are five predefined TSO users in the MVS Tur(n)key System: Userid Description Password IBMUSER Emergency user HERC01 System Programmer Userid HERC02 System Programmer Userid CUL8TR HERC03 Standard user HERC04 Standard user PASS4U