Populating the List Box (Forms)

I am not at all sure I am in the correct place and if not please advise.

I am trying to create a simple form in OOo Writer and would like a "List 
Box" what I need is simple as I require a simple list of items to choose 
from. What I cannot figure out is how to populate the List under "List 
Entries"? It seems it will only accept a single item/entry?