The whole section of coding would go within the sub for your custom search form within your html.pl file.

There are examples and instructions for how to add the custom form to your footer, and also how to direct searches to this form rather than the default keyword search form in the FAQ noted below under the section for "Searching".

You would can even have both search forms available to your users. But you will need to create a new sub for your search form and include the fields you want to search on, and then also the coding above to search by time frames.

Unoffical DBMan FAQ

http://creativecomputingweb.com/dbman/index.shtml/