Plug the J2534 to the OBD of your car, turn the Maxisys tablet on and click the VCI icon on the bottom of the tablet. The MaxiSys will automatically start scanning for available VCI devices, on the right side you will see the detected BT devices. The device VCI serial number (usually starting with CNJB) will be displayed in the list of found devices. Click to unpair the old J2534, then pair your new J2534.
The VCI button on your tablet will display a green tick icon. This means you are connected to the VCI.