To set up a "Find Screen", I'd create a layout with a global field that corresponds with a field in my table that I want to search when the find is performed. I can either have a scritp that switches to this layout or a script that displays this window in a new modal window. Either way, the user fills in data in the fields and then clicks a button to perform a script that uses the data in the global fields to perform the needed find and display the results.
See this thread for a number of script examples that use data entered into global fileds to construct find criteria and then perform the find. Scripted Find Examples
See below for an image of just such a find screen I use in some of my solutions when performing a find using date criteria: