ESP32 pins define of KC868-Server

[Naif]

Thanks for your prompt response.
Considering port-2 is the one that connected to the ARM not Port-1:
Is this the right command to switch-on relay1:
Serial2.begin(115200, SERIAL_8N1, 16, 17);
Serial2.write("RELAY-SET-255,1,1");
?
Regards;