I've bought from YMDK in the past, though I have not tried the wings.
If the PCB supports QMK, and especially QMK/VIA, most likely YMDK would flash the VIA firmware for you already.
So download VIA, runs it (VIA will say searching for compatible keyboard), and plug in the keyboard.
If VIA detects it, then you're game. Simply go to the FN layer and see if there's a "RESET" bound to any key.
If not, you can bind it yourself.
But if VIA is already flashed, you don't really need to reflash the firmware again, you just use VIA to set your layout. (unless there's a known bug fixed for your board's VIA firmware down the road)