describe templating steps mechanics for Package CR

**Describe the problem/challenge you have**

not clear from the docs what kbld step does in example Package CR. consider adding docs for general App CR templating mechanics.

Start with the documentation example for the Package CR and trace what the kbld step does, then compare it with the general App CR templating mechanics mentioned in the issue. Done means the docs clearly explain the templating flow and the role of kbld in the example.

Written by the indexing model from the issue text.