I'm no expert on this subject by any means. However, I am pretty sharp on the Catia documentation, and if your answer is to be found in the docs - which I have to assume you are asking about, by virtue of the title of your post - then you will find it under the CATIA Infrastructure Installation Guide, or possibly the CATIA Infrastructure User Guide.
I'm definately not an expert on this topic but if I understand your question, what you might wanna look up is CAA. It allows you to develop custom applications, create your own workbenches, ...... I'm assuming that's sort of what you are interested in.
In the help CAA is under Automation in the Infrastucture section as solid7 mentioned. But it requires a license.
More info see