If you are not familiar with lists, please see Chapter 8 "Introduction to Lists" in my e-book "Guide to App Inventor 2:Tutorial - The fast and easy way to create Android apps."
Fa o sa bone dintlha tseno, tsweetswee latela ditaelo tse di mo setlhogong se se reng "Simolola go Dirisa JW Library - Android," mo setlhogwaneng sa Bona Tsa Bosheng.