How to save(post) list

Hi,

I have Offer class, OfferItems class and Item class and tables in database. Offer can have many items.

I want to edit and save Offer with attributes(email, shipping etc) and edit and save list of Items(id, quantity).

I can do edit screen for Offer and save Offer to database. But I cant figure out how to do edit screen for list of items where you would add items and save them to database. Could somebody help? It has to be all on one page.