How to use IR's (Imuplse responses) in mainstage or any other software in a if not in MainStage on a macbook?

I downloaded a Guitar IR(impulse response) file, but I'm currently struggling with how to use it in my software (MainStage). I would greatly appreciate it if someone could provide a step-by-step guide on how to use IR files in MainStage or any other software on a MacBook. Thank you!