You can toggle the Quick Tap (SOCD) function ON/OFF using the FN + (L)SHIFT combination, with A and D keys supported by default.
You can change which keys are applied to Quick Tap in the driver: bbb.pulsar.gg
When the combination keys are pressed, the SHIFT key will light up with a white LED, indicating that the last input key has been registered.
If you play games like Counter-strike where SOCD is banned, you should keep Quick Tap OFF, learn more here.