can someone explain what VST and RSCA are? I see the buttons but I don't know what they're supposed to do

I think you mean VSC.

VSC is the vehicle stability control that integrates ABS, traction control, engine control to prevent the vehicle from skidding when cornering. Also prevents oversteering or understeering & will try to save you from losing control and detects angular momentum and tries to control direction of skid.

RSCA (Roll Sensing Curtain Airbag) turns off the side airbags.....so they do not deploy during heavy duty offroading intended to be used in situations involving a high degree of sideways slope.