Interaction between conceptual structure design and physical structure design in powerdesinger

The new project is about to begin, and the customer's requirements for documents have been improved, which is a great test for us.
As a large company like the customer side, the requirement standards are understandable, but they have increased the workload for us. In the words of leaders, the development cost has increased.
However, I personally think it is also a good learning opportunity and a challenge.
I have been designing databases all the time, but what is the essence of database design? How can we design a database reasonably? I have not considered these issues.
Today, I suddenly thought that I should learn how to design the "concept structure" of the database before the formal start, so that I can't be caught off guard after the battle.
Fortunately, the current tool is really powerful. I use powerdesigner. Subjective imagination should involve a reverse approach from physical models to conceptual models.
I finally found it.
The tool menu has three options: generate a conceptual data model, generate a physical data model, and generate an Object-oriented Data Model.

For example. In the physical data model of the project, after "generate conceptual data model" is selected, the conceptual data model of this model is automatically generated. You can also select a conceptual data model to generate a physical data model. Very easy to use.

This is just the beginning for me. Let me see another world. I really don't know much about conceptual data models. At the same time, when I used powerdesigner to design a conceptual model, I found that the data type of its attributes was very strange. Why?
In addition, I don't know the theory or the use of tools. I can also use the functions provided by tools in a more in-depth manner to make my work more clear and complete. Be enterprising!