How is clay made my brother wants to know

Clay is usually made from soil, and minerals. Or it can be artificially made in factories. 

Clay is made from soil or in a fcatory

This sounds like a personal reflection on something you did. it is asking the hardest part, or a part you may have struggled with on an informal interview you must have done. it is also asking advice you'd give someone else for the process of completing an informal interview, so you should write something that would . for example, maybe the first thing they should do, something they should include.