timer code

I am making a simulation time bomb for airsoft. I have the basic code that works but now i need to integrate a timer that starts at 60 and counts down displaying the current time left on the lcd with a beep every other second. I found that this library is the best for what I am trying to do, but I am having trouble with the code. https://playground.arduino.cc/Main/CountDownTimer . Below is the code I have so far. With a arm and start switch. Everything works except the timer functions.

#include <CountUpDownTimer.h>


#include <SoftwareSerial.h>


const int lcdpin = 1;
const int ledgreen = 2;
const int ledred = 3;
const int armbutton = 4;
const int startbutton = 5;
const int tpin = 6;
int buttonState = 0;
int buttonState1=0;
int CountUpDownTimer(SetTimer(60))
CountUpDownTimer(DOWN);
SoftwareSerial mySerial = SoftwareSerial(255,lcdpin);

void setup() {
  pinMode(lcdpin, OUTPUT);
  pinMode(ledgreen, OUTPUT);
  pinMode(ledred, OUTPUT);
  pinMode(armbutton, INPUT);
  pinMode(startbutton, INPUT);
  pinMode(tpin, OUTPUT);
}
void loop() {
  digitalWrite(lcdpin, HIGH);
  mySerial.begin(19200);
  delay(5);
  mySerial.write(12);
  delay(5);
  mySerial.write(17);
  delay(5);
  digitalWrite(ledgreen, HIGH);
  mySerial.write("Ready");
  while(digitalRead(armbutton)== LOW);
  buttonState = digitalRead(armbutton);
  if(buttonState == HIGH) {
    digitalWrite(ledred, HIGH);
    mySerial.write(12);
    delay(5);
    mySerial.write("Armed");
  }
  
   while(digitalRead(startbutton)== LOW);
   buttonState1 = digitalRead(startbutton);
    if(buttonState1 == HIGH) {
      CountUpDownTimer(SetTimer(60));
      CountUpDownTimer(StartTimer());
      mySerial.write(148);
      mySerial.write(CountUpDownTimer(ShowSeconds()));
      while(CountUpDownTimer(ShowSeconds()) > 0);
      if(CountUpDownTimer(ShowSeconds()) == 0) {
      digitalWrite(tpin, HIGH);
      }
    }
    
}

airsoft_bomb.ino (1.33 KB)

Not everybody can open attached ino files (think cellphone users). The file is small enough to post inline. See the sticky how to use the forum; it has a section hoe to post code,