Siemens pl:c cpu 222

Hello,
I have finally got a new SIEMENS PLC CPU222 (digital I/O). And I want to make a chocolate tempering machine. Always, Step 1 of any project is difficult to start with, I am an engineer and I know how to work with electronics and Step 7 programming, but if someone of you help me with doing the first step. I know this is not a good question but I am currently out of ideas.

http://accautomation.ca/five-steps-to-plc-program-development/

1 – Define the task:
What has to happen?
2 – Define the Inputs and Outputs:
3 – Develop a logical sequence of operation:
Fully understanding the logic before starting to program can save you time and frustration.
4 – Develop the PLC program:
5 – Test the program:

I hope this helps you out,

Sir, and how do I do the mechanic part ?

Mechanical Part? I do not understand what you mean. Have you reviewed the link I provided above?

Regards,

yes sir, I saw it. I mean that the body of the machine, how to design and who to ask to build it, before adding PLC and sensors to it and program it ?