It was a bit ago so I don't remember the exact process, just that it was very intuitive. Install the joystick software and make sure it's all up to date and being detected by your computer. Once that's set, just open antimicro, it detects the inputs and lets you assign joystick/throttle buttons to keys and the joystick axes to mouse movements.
It should work with any joystick/throttle theoretically, but I used the t.flight hotas one combo and it worked without issue, and if I remember correctly I read somewhere here that the ASTB uses some variation of the tfllight hotas series. If you have any issues hmu and I'll try to help the best I can!