Problem w/ compilation that i cant understand

Im doing a project. I want to send data from Pulse sensor to my database. Pulse sensor is working good same as database but i cant connect this two things. Im posting my code, my bug and code that im using as a base for my code.

This is my code :

#include <PulseSensorPlayground.h>
#include <SPI.h>
#include <Ethernet.h>
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //Setting MAC Address


const int PulseWire = 0;
int Threshold = 513;

PulseSensorPlayground pulseSensor;

float pulsData;

char server[] = "";
IPAddress ip(192,168,1,163); 
EthernetClient client; 

/* Setup for Ethernet and RFID */

void setup() {
//  if (Ethernet.begin(mac) == 0) {
//  Serial.println("Failed to configure Ethernet using DHCP");
//  Ethernet.begin(mac, ip);
//  }

/* Infinite Loop */
void loop(){
int myBPM = pulseSensor.getBeatsPerMinute();
   if (pulseSensor.sawStartOfBeat()) {
    Serial.println("♥  A HeartBeat Happened ! ");
    Serial.print("BPM: ");
  delay(30000); // interval

  void Sending_To_phpmyadmindatabase()   //CONNECTING WITH MYSQL
   if (client.connect(server, 80)) {
    // Make a HTTP request:
    Serial.print("GET /kod/skrypt.php?puls=");
    client.print("GET /kod/skrypt.php?puls=");     //YOUR URL
    client.print(" ");      //SPACE BEFORE HTTP/1.1
    client.println("Connection: close");
  } else {
    // if you didn't get a connection to the server:
    Serial.println("connection failed");

This is my bug:

Arduino:1.8.13 (Windows Store (Windows 10), Płytka:"Arduino Uno"

C:\Users\Acer\AppData\Local\Temp\ccgva8RR.ltrans0.ltrans.o: In function `begin':

C:\Users\Acer\Documents\Arduino\libraries\PulseSensor_Playground\src/PulseSensorPlayground.cpp:56: undefined reference to `PulseSensorPlayground::UsingInterrupts'

C:\Users\Acer\Documents\Arduino\libraries\PulseSensor_Playground\src/PulseSensorPlayground.cpp:57: undefined reference to `PulseSensorPlaygroundSetupInterrupt()'

collect2.exe: error: ld returned 1 exit status

exit status 1

Błąd kompilacji dla płytki Arduino Uno.

Ten raport powinien zawierać więcej informacji jeśli w 
File -> Preferencje zostanie włączona opcja "Pokaż
szczegółowe informacje podczas kompilacji"

and this is the working code but not for my sensor :

Pls help me guys I really dont know what im doing wrong and i cant move on.

I found soulution. Definition should be above the included libraries. Thats the bug. Ty for reeding.