Work for Pay

I am struggling with the code and was wondering if anyone would be able to help.
I have a database of locations, with a few details and an image.

I then have a page with a gallery that displays the images. I would like to be able to a filters to the page. I have added 3 dropdown boxes with the options, but can’t get it to filter the gallery.

The first dropdown list is location info
The second dropdown list is a more focused location info (so ideally would cascade from the selection from the first dropdown)
The third dropdown is to allow selection by ‘type’. This would need to filter on a number of boolean fields.

Finally I would like to add a button that will link to a page depending on the first dropdown

Many Thanks,