The easiest thing to do is to keep the information in hidden fields, passed from form to form.

Because you have so much data, though, you may find it better to use sessions. Search CPAN for Session to find several modules that can help you with this. Sessions store a unique identifier on the user's client, in a hidden form field or a cookie, then store all of the information associated with that user on the server. When the user connects, it figures out where to get and store that information by the unique identifier.