Forms :: Parametric Search Based On Multiple Fields

I want to create a parametric search for tools on the shop floor based on multiple fields [using VBA]

I've had a good search and turned up lots of useful things; but each example insofar has been fairly specific as opposed to a guide on how to implement it in a wider setting.

Let us say, for example, that my database has three fields each with a bound combo box: location; house-type; number of bedrooms

As I type in location, I want it to filter my results in the other boxes to that location (should be a simple case of applying a filter?) - which leaves me with all the house-types and bedroom-counts in that location.

As I type in the house-type, I want it to then narrow down the search again to filter the "location"+"house-type" to leave me with the available number of bedrooms.

What is the best way to implement this, given that I have about 20 fields*, some of which will inevitably be blank: as the user types in (or selects using combo boxes) the data required, it narrows down the search - and finally there's a "search all" button which returns all results matching the current criteria.

When I say "implement" I mean what underlying structure should I use. Is it best to create a query and update the query as items are entered, or would it be better to filter the form that's having the data entered?

The fields are organised sensibly into sub-forms for various characteristics (i.e manufacturing data, materials data, cutting data, etc, etc), don't worry - it's note a huge mess - and the code is all there to pull the data together as required!