help with dfplayer mini library

my project includes arduino, push button, dfplayer mini(https://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299) and a speaker
when button is pressed, the dfplayer mini plays all the song present inside mp3 folder on the SD card.
i am using " myDFPlayer.enableLoopAll() " to play all the songs.
but when there is a switch from one song to another i need a 2sec pause between.
how to add this delay?

/***************************************************
  DFPlayer - A Mini MP3 Player For Arduino
  <https://www.dfrobot.com/index.php?route=product/product&product_id=1121>

 ***************************************************
  This example shows the all the function of library for DFPlayer.

  Created 2016-12-07
  By [Angelo qiao](Angelo.qiao@dfrobot.com)

  GNU Lesser General Public License.
  See <http://www.gnu.org/licenses/> for details.
  All above must be included in any redistribution
 ****************************************************/

/***********Notice and Trouble shooting***************
  1.Connection and Diagram can be found here
  <https://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299#Connection_Diagram>
  2.This code is tested on Arduino Uno, Leonardo, Mega boards.
 ****************************************************/

#include "Arduino.h"
#include "SoftwareSerial.h"
#include "DFRobotDFPlayerMini.h"

SoftwareSerial mySoftwareSerial(10, 11); // RX, TX
DFRobotDFPlayerMini myDFPlayer;
void printDetail(uint8_t type, int value);
const int buttonPin = 4;
int buttonState = 0;

void setup()
{
  mySoftwareSerial.begin(9600);
  Serial.begin(115200);

  Serial.println();
  Serial.println(F("DFRobot DFPlayer Mini Demo"));
  Serial.println(F("Initializing DFPlayer ... (May take 3~5 seconds)"));

  if (!myDFPlayer.begin(mySoftwareSerial)) {  //Use softwareSerial to communicate with mp3.
    Serial.println(F("Unable to begin:"));
    Serial.println(F("1.Please recheck the connection!"));
    Serial.println(F("2.Please insert the SD card!"));
    while (true);
  }
  Serial.println(F("DFPlayer Mini online."));

  myDFPlayer.setTimeOut(500); //Set serial communictaion time out 500ms
  pinMode(buttonPin, INPUT);
  //----Set volume----
  myDFPlayer.volume(30);  //Set volume value (0~30).
  myDFPlayer.volumeUp(); //Volume Up
  myDFPlayer.volumeDown(); //Volume Down

  //----Set different EQ----
  myDFPlayer.EQ(DFPLAYER_EQ_NORMAL);
  //  myDFPlayer.EQ(DFPLAYER_EQ_POP);
  //  myDFPlayer.EQ(DFPLAYER_EQ_ROCK);
  //  myDFPlayer.EQ(DFPLAYER_EQ_JAZZ);
  //  myDFPlayer.EQ(DFPLAYER_EQ_CLASSIC);
  //  myDFPlayer.EQ(DFPLAYER_EQ_BASS);

  //----Set device we use SD as default----
  //  myDFPlayer.outputDevice(DFPLAYER_DEVICE_U_DISK);
  myDFPlayer.outputDevice(DFPLAYER_DEVICE_SD);
  //  myDFPlayer.outputDevice(DFPLAYER_DEVICE_AUX);
  //  myDFPlayer.outputDevice(DFPLAYER_DEVICE_SLEEP);
  //  myDFPlayer.outputDevice(DFPLAYER_DEVICE_FLASH);

  //----Mp3 control----
  //  myDFPlayer.sleep();     //sleep
  //  myDFPlayer.reset();     //Reset the module
  //  myDFPlayer.enableDAC();  //Enable On-chip DAC
  //  myDFPlayer.disableDAC();  //Disable On-chip DAC
  //  myDFPlayer.outputSetting(true, 15); //output setting, enable the output and set the gain to 15



  //----Read imformation----
  Serial.println(myDFPlayer.readState()); //read mp3 state
  Serial.println(myDFPlayer.readVolume()); //read current volume
  Serial.println(myDFPlayer.readEQ()); //read EQ setting
  Serial.println(myDFPlayer.readFileCounts()); //read all file counts in SD card
  Serial.println(myDFPlayer.readCurrentFileNumber()); //read current play file number
  Serial.println(myDFPlayer.readFileCountsInFolder(3)); //read fill counts in folder SD:/03
}

void loop()
{
  buttonState = digitalRead(buttonPin);
  if (buttonState == HIGH) {
    Serial.println("hi");
    myDFPlayer.enableLoopAll(); //loop all mp3 files.
    delay(15000);
    
  }

}
    myDFPlayer.enableLoopAll(); //loop all mp3 files.

I would think that there is a function in the library that plays a single file and maybe even one that plays the next file.

The next() function looks a likely candidate, but I don't know anything about the library. Try substituting

myDFPlayer.next();
delay(2000);

Look at the examples with the library for more information.