LCD Timer without delay

Hello everybody, i have been trying to get my timer working correctly without the usage of a delay function.
Is someone albe to find a solution for me to get it working without the delay function?
I have been trying many different things but havent found a solution yet…

#include <LiquidCrystal.h>
#include <SimpleTimer.h> 
#include <TimerOne.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
  int plusPin = 6;
  int minPin = 7;
  int I=0;
  int U=0;
  int T=0;
  long previousMillis = 0;
  long interval = 1000;
  

void setup() {
  Serial.begin(9600);
  pinMode(plusPin, INPUT);          //Declare PINS
  pinMode(minPin, INPUT);           
  lcd.begin(16, 2);                 //Declare LCD
  lcd.setCursor(0,0);               //Declare Cursor
  lcd.print("Verkeerstelling");     //Print tekst
  
  delay(10000); 
}

void loop() 
{
  I=0;
  U=0;
  T=0;
  
  
  lcd.clear();                      //Clear LCD
  
  if (digitalRead(plusPin) == HIGH)  //Set pin as formule
  {
  (I++);
  }
  if (digitalRead(minPin)== HIGH)   
  {
  (U++);
  }
  lcd.setCursor(0,0);               //Printing In: (I) and Uit: (U)
  lcd.print("In: ");
  lcd.setCursor(4,0);
  lcd.print(I);
  lcd.setCursor(8,0);
  lcd.print("Uit: ");
  lcd.setCursor(13,0);
  lcd.print(U);
  T = (I-U);                        //Sum of I - U making total of T  
  lcd.setCursor(0,1);               //Printing Totaal: (T)
  lcd.print("Totaal: ");
  lcd.setCursor(8,1);
  lcd.print(T);
  lcd.setCursor(13, 1);

  int n = 300;                      //Set countdowntimer
  
 
  for ( n = 300; n > 0; n--)        //Looping countdowntimer
    {
                                                                                                                                    
      
  
    delay(1000);  
    lcd.setCursor(13, 1);
    lcd.print(n);                  //Print timer
    lcd.print(" "); 
    
   
    }
}

i have been trying to get my timer working correctly without the usage of a delay function

    delay(1000);  
    lcd.setCursor(13, 1);

What's that then?

Yes i know, but the fact is that that the only way i have got it working. But i need to find another way to get it working.

In the first post of this Thread I wrote an extended demo of the concept in the Blink Without Delay example sketch. It may give you some ideas.

...R

But i need to find another way to get it working.

You mean like the blink without delay example?