The Combo Box has a Click Event. When a value in the Combo List Box is clicked, it raises the Combo_Click() Event. Select the Combo1 Control from the Control List box on the left hand side of the IDE. And then click on the Combo_Click Event. That should set code for the Click Event in the IDE editor.
Within that Click Event Write code to Add the contents of the currently selected item into the list box. The action of clicking on the Combo Box should set the current selection to the value you want to transfer to the List Box. The ListBox has an add function which you should use to add the value of the combo box to the list box.
You should be able to figure it out from there.
