Hello. You did not enter the text to which this question refers, which makes it impossible for this question to be answered satisfactorily. However, I will try to help you in the best possible way.
The central idea of a text is important because it allows you to have a full understanding of what the text means, that is, the central idea is the positioning of the text around a message that it wants to disseminate and that will give the framework necessary for you to understand it and understand the whole story covered.
