How Do I Arduino #Include<Button.H> Compile Error

typedef unsigned char byte;
// included libraries
#include <LiquidCrystal.h>
#include <Button.h>

// pin definitions
#define START_BUTTON_PIN 6
//-7-

// variable initialize 
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
Button start_button = Button(START_BUTTON_PIN, BUTTON_PULLUP);
//-8-

unsigned long timerInterval = 1000; // duration variable in milliseconds
//-1-
unsigned long timerLastStart = 0;  // Last Start Time variable in milliseconds
//-2-
int secondCount1 = 0;
//-3-

//-5-

void setup () {
  Serial.begin (9600);
  Serial.println("Non Blocking Timer");
  Serial.println("Lets Begin");

  lcd.begin(16, 2);
  lcd.setCursor(0, 0);
  lcd.print("Timer: ");
  lcd.print(secondCount1);
  lcd.print ("s");

  //-6-

}

void loop () {

  if (start_button.uniquePress ()) {
  } 

  //-9-

  if(millis() - timerLastStart > timerInterval) {
    timerLastStart = millis();
    // event code
    secondCount1++;
    lcd.setCursor(0, 0);  
    lcd.print("Timer: ");
    lcd.print(secondCount1);
    lcd.print ("s");  
  }

  //-4-

}