Newbie need help in Arduino+Bluetooth & App Inventor

Projects General Guidance
1

Greetings Arduinians,,

My project has been going very well, but i am stuck with the last part. I was wondering if anybody has/knows the source code for sending bytes (ASCII) from Arduino+Bluetooth to my App Inventor. Here is what i have for communicating with Serial Monitor of Arduino but i cannot figure out how to communicate with App Inventor

Here is the code for Communicating with serial monitor.

       {  
         digitalWrite(ledPin_1, HIGH); 
         Serial.println("Press");
        
         bluetooth.write(buttonState);
         Serial.println('3'); 
         delay(1);
   }

I want my App Inventor to receive the signedbyte 51 (51 = decimal, 3 = Symbol) based on the ASCII Coding. And when that is received, my "Label" will show the changes.

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