You need to set a button on the first form to open the second form, and then link the second form's record source to this list box. The wizard should do this for you automatically if you select open the form and display related data.
If not, you need to capture the bound values of the list box in variables, and then create a link criteria to your second form. I can do this with single values in combo boxes, but have not done this for n values from list boxes. I know I have seen a post on this recently.