Adobe LiveCycle

Need some help to create a pick ticket, or shopping list of sorts.  Page one would have a list of all available items that you can select from, and page two, fields would automatically be filled in from the selections on page one.  I am thinking that it would be a type of if, then, else formula.  I would want the fields to fill in, in sequence, so I am also thinking that if a field value is null, one of the items could fill this space, if the field contains data, then it would need to use the next available field that has no value.  If an item is later un-selected, then I would want everything to shift upwards if possible.  Hope this makes sense, and I am open to other suggestions that may be much simpler or smarter.