Hello, I'm having trouble to figure out how to do this, I have a simple window with 3 buttons, each button should change the content listed on the list below them but I'm really not sure about how to do it.

This is the code for the window:
---
open
������ "Abre la ventana principal del Sistema de Gestion Bibleotecaria"

������ | builder contain |
������ builder := UITheme builder.
������ contain := builder newColumn: {builder newRow: {
������ ������ ������ builder newButtonFor: self action: #onPrestamosClick label: 'Prestamos'�� help: ''.
������ ������ ������ builder newButtonFor: self action: #onMaterialesClick label: 'Materiales'�� help: ''.
������ ������ ������ builder newButtonFor: self action: #onSociosClick label: 'Socios'�� help: ''}.
������ ������ ������ builder newColumn: {
������ ������ ������ builder newListFor: self list: nil selected: nil�� changeSelected: nil�� help: '' }.}.
������
������ (contain�� openInWindowLabeled: 'Babel') extent: 600@600.
---

How should I define #onLabelClick to set the list to for example: Prestamo database.

Thanks in advance.