how to debug batch job

    SBMJOB CMD(CALL PGM(testlib1/TEST10)) HOLD(*YES)      
    WRKSBMJOB --->>  *Job id                              
                     *User Name                           
                     *Job Number                          
    STRSRVJOB                                             
    STRDBG PGM(testlib1/TEST10) UPDPROD(*YES) OPMSRC(*YES)
    F12                                                   
    WRKSBMJOB 6-RELEASE                                   
    F10                                                   
    DSPMODSRC    SET THE BREAK POINT.  F12                
    ENTER.                                                
    DEBUGING........                                      
        .......                                           
    ENDDBG                                                
    ENDSRVJOB