What is production support procedure? How to login production support? what is transaction code?

1.  The customer or the end user logs a call through any tool or     by mail tools are:
    -(RADIX).
    -Remedy
    -Service Desk (SD4)
    -Perigreen 
    -lotus notes

 2.  Each one of the support team is a part of support group.

 
 3. Whenever a customer logs a call he /she have to mention
    to which work group (by name). 

 4. Once the calls came to the work group the support
    consultant or the team needs to send an IR (Initial
    Response) to the user depending upon the priority of the
    calls. (Top, High, Med, Low, None) 

 5. Then the error is fixed, debugged by the support
consultant or the team. Then after testing properly by
generating TR (Transport Request through the basis admin) 
 6. Then it is informed to the end user/customer/super user
about the changes which have moved to the production server
by CTS process. 

These are the process.  In summary, what I understand is
that if any configuration or customization is required to
solve the issue, then the consultant have to work on DEV
Client, then the end user will test it in the QA client and
after approval the BASIS consultant has to transport it to
the PRODUCTION client.