How do I use the IR impulse function of the Tonelib GFX software?

Impulse responses have to do with room dynamics, reverb, cab charasteristics etc. They are not guitar sounds. Choose the Guitar IR Cab, disable the cabinet emulation, and play with the different selections in the options.

I haven't found out how to use CUSTOM IR responses yet but something tells me I just have to load them into the Impulses on the right then drag it into a slot. (It drags them with an IR Processor). Though I might be wrong. Those might be only for reverb, and not cabs.