code: def set_widgets(self):
          
          self.clear_further_steps()
          # Set widgets
          self.lblBandSelector.setText(tr(
              'Please select which band that contains the data that you want to '
              'use for this layer.'))
          self.lstBands.clear()
          band_num = self.parent.layer.bandCount()
          for i in range(band_num):
              item = QListWidgetItem(
                  self.parent.layer.bandName(i + 1),
                  self.lstBands)
              item.setData(QtCore.Qt.UserRole, i + 1)
              self.lstBands.addItem(item)
          existing_band = self.parent.get_existing_keyword('active_band')
          if existing_band:
              self.lstBands.setCurrentRow(existing_band - 1)
          else:
              # Set to Band 1 / index 0
              self.lstBands.setCurrentRow(0)
docs: Set widgets on the LayerMode tab.