problem on my new arduino project using NRf Toolbox for BLE and arduino uno

Hi, I’m an arduino newbie, and I am on this hard mission with my team. We are trying to build an Arduino Iot house, and the things that we are trying to add is this A/C controlled by NRF Toolbox UART option. what I am trying to do is change the INT variable ‘int nTargetTemp’ by +1 or -1 using UART.

/*
 
#include "DHT.h"

#include <LiquidCrystal_I2C.h>


#define DHTPIN 2
#define DHTTYPE DHT11

DHT dht(DHTPIN, DHTTYPE);




int nTargetTemp ;


int RED_LED = 4;


int GREEN_LED = 3;



LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  
  Serial.begin(9600);
  pinMode(RED_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);
  
  dht.begin();


  lcd.begin();

  lcd.backlight();

  nTargetTemp  = 33;
}

void loop() {


  lcd.setCursor(0, 0);
  

  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature();

  if (isnan(humidity) || isnan(temperature) ) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }
  Serial.println("OK  read from DHT sensor!");


  Serial.print((int)temperature); Serial.print(" *C, ");
  Serial.print((int)humidity); Serial.println(" %");

  String szLine1  , szLine2 ;
  
  int nCurrentTemp ;

I’m trying to make this work in a way like this. {Upon receiving ‘up’ from bluetooth connected phone,add +1 to the int variable ‘int nTargetTemp’.} => received up, change int var ‘nTargetTemp’ to 34 from 33.

Please help me.

Instead of jumping into the deep end of the pool, you should make sure that you are able to write code using the UART. In other words, if you receive the word 'up' from Bluetooth terminal app, display what is received on the Serial Monitor. If you cannot do this, you have no hope of going any further.

.