Save to disk, then from the plugin click the 'File' button and navigate.
They are basically 'images' of real world gear. They get driven a standardized impulse through them and the result is recorded. Then the modified impulse is loaded to a plugin like this and it will emulate the sound of the original unit with the impulse. Compressors, preamps, amp simulations, reverbs, you name it. There's also lots of 'real space' impulses recorded in missile silos and where ever, but that's more for the impulse reverb units. Boogex works best on compressor and amp simulation impulses.