Time and TimeAlarms Libraries – Ask here for help or suggestions

How is "adjustTime(adjustment);" command used ?

I want to send a command to my program ,so an hour or a day is added to timer.
Later those commands will be sent by the press of a button

Is this command ok ? adjustTime(hour()++);

#include <Time.h>  


void setup()  {
  Serial.begin(9600);
 
  Serial.println("sending time to arduino");
  setTime(0,0,0,1,1,2000);
}

void loop(){
digitalClockDisplay();
delay(1000);
}

void digitalClockDisplay(){
 
  Serial.print(day());
  Serial.print(" ");
  Serial.print(hour());
  printDigits(minute());
  printDigits(second());
  Serial.print(" ");
  Serial.print(day());
  Serial.print(" ");
  Serial.print(month());
  Serial.print(" ");
  Serial.print(year()); 
  Serial.println(); 
}

void printDigits(int digits){
   Serial.print(":");
  if(digits < 10)
    Serial.print('0');
  Serial.print(digits);
}