Newbie - One screen showing using three models

I have a screen for creating a Quote (new.rhtml in the views/quotes
folder).

That screen is based on the Quotes model (which holds all the general
information about the quote ).

I want to include tables of data from two other models in this form.
Right now I'm rendering partials = views/quote_details/
_quote_details_form.rhtml (which is a table for entering all the line
items for the quote) and views/quote_commitment_details.rhtml (a table
for entering multiple delivery dates per line item, if needed).

The problem is: I have three submit buttons on my screen and I'm not
sure how to get rid of them.

Can anyone explain what to do or recommend another way of achieve
this?

Thank you!

PS - Also, is there a way to limit the size of a <% text_field %>?