[Prism] How to save a form?

I can't figure out how to save a form page with Prism.
I have let's say an EntryCell like this.

    <EntryCell Label="{Binding Source={x:Static local:DialogMessage.FormAuctionName}}"
                               Text="{Binding Auction.Name, Mode=TwoWay}"></EntryCell>

When I click the Save button I imagined that my property Auction.Name would contain the new value I typed in it.
I guess that is not how it works? How do I get the form values on save?

Sorry I am kind of new to XF and Prism..

Thanks