What is the best way to present a question where user has to select multiple options?

I am working on a mobile app where, user has to select few categories and subcategories to proceed. eg: Let’s assume I have four categories A,B,C & D. All these four categories have subcategories which are 10-20 in numbers.

• My goal here is to create question papers for primary school kids. The app is for the parents. Let’s say subjects are the primary categories. Subcategories include which chapters to include in the test.

• There are four subjects and each subjects have 10-15 chapters.

• He/She can select more than one category/subcategories.

• User will see a summary screen of the items selected.

He/She can select more than one category/subcategories. User will see a summary screen of the items selected.