1.select the cell where you want a list.
2.select menu: Data>Validation
3.under Settings Panel:
- Under Allow: select List;
- Under Sources: select the field where you put your list content. or select the icon in the right side of sources box: for example, if you want the listbox contains a, b, c, d, e... you can put a b c d e in cells H2, H3, H4, H5, H6. The in sources you put in =$H$2:$H$6 or select the icon to pick the fields by mouse.
Usually, those list content are put in columns far far away, such as colume Z or AA, so you won't see it. And you can shrink the column width to make them sort of disappeared.
If you still have problem, send me your phone, I will let you know.