How do you divide the application into different sections to create scripts?

First of all, the application is divided in different parts when a business analyst writes the requirement document (or Use Cases or Design Document), he/she writes EACH requirement document for EACH module. Let us say, if there are 12 different modules in an application that a business analyst has written the requirements for, then a tester would write the test cases for each module, which means in 12 different sections. This is the standard practice. There might be scenarios where you might have to break down scripts into sub-categories. For example, if a tester is writing a script for Login Page, he/she might write one for positive and negative testing and another sub-set of test cases would be for error message when the wrong information is entered. In short, the test cases are divided according to the modules.
(The following questions were asked to Padma in one of her interviews very recently)
(This question is asked to check how ambitious you are as far as your career is concerned, whether you like the job you are doing and so on. Therefore, no matter what, you should stick to your QA job at this point and say that you love this so much and your goal is some thing similar to the one below)