Sigh. This is not a CICS start up job. This is a mess. I suspect you just coded your SIT entries into your job stream and hence the missing SYSIN DD statement message.
If you do not have start up JCL handy, you need to look in the CICS manuals (find them at http://www.ibm.com
if nowhere else) for the actual JCL to start up CICS. You also need to know of you are using a started task or batch job for CICS as the JCL is somewhat different depending upon which you use. At a minimum, you need to execute the CICS program with a STEPLIB (unless the CICS libraries are in the link list), not to mention the DFHRPL DD statement for application programs.
Are you aware that the SIT is compiled (actually, assembled) using the appropriate CICS batch utility program? The assembly process creates a load module, and the load module must be available to the CICS region when the start up JCL is executing. Have you verified that the defaults for the missing SIT values are all valid for your region? Have you verified that you have specified all SIT parameters that are required to be provided? Once assembled, you can provide overrides to the existing SIT when starting up the CICS region, but you must first have a valid SIT to do that.
If you have never brought up a CICS region, this is NOT a task for a student or beginner. You must get the various table elements assembled correctly, ensure the security system is configured correctly, ensure the Workload Manager is configured correctly, ensure VTAM is configured correctly, ensure the CICS region terminals are configured correctly, and so forth and so on. In other words, there is a LOT of work involved in getting a new region running.