plz help me on the coding
In order for us to help you, you first have to have some code and show us it, along with details of what isn’t working,
But if your don’t have any code, then please be aware that we are NOT going to do it for you… However you could start with reading some of the already provided documentation and examples.
http://help.blynk.cc/how-to-connect-different-hardware-with-blynk/arduino/usb-serial