There’s a few people with, and threads about, the YL620A. I have one of these running my spindle.
The thread here talks about it.
The FWD needs to be hardwired to XGND to make the spindle run forwards by default.
Speed control is done using VI1 and GND, but this particular VFD does not accept PWM. It only accepts an analogue signal. You need a PWM to 0-10V board to convert the ShapeOko PWM to an analogue signal, such as this.