RFID Reader, error

Good evening guys (first of all, sorry, i know that my english is bad),

I am having some problems with Arduino UNO, all works great but now, looking into internet, i found this code:

//Módulo Lector RFID-RC522 RF
#include <SPI.h>
#include <MFRC522.h>
RFID rfid(10,5);
void setup()
{
 Serial.begin(9600);
 SPI.begin(); rfid.init(); 
 
}
unsigned char het[16]={'H','E','T','P','R','O',' ','R','F','I','D',' ','5','5','2',' '}; //Declaracion de cadena de caracteres
unsigned char *writeData=het; //asigna het a char tipo puntero
unsigned char *str; //char tipo puntero utilizado para la función de lectura de un bloque
 
void loop()
{
 if (rfid.isCard()) {
 rfid.write(8,writeData); //Función escritura (num de bloque, string)
 rfid.read(8,str); //Función lectura (num de bloque, str) guarda lo que está en el bloque a str
 Serial.print(str[0]); //Imprime lo que se guardó en str de la funcion read
 }
 rfid.halt();
}

And getting this errors:

LecturaBloqTags_RFID:4: error: 'RFID' does not name a type
 RFID rfid(10,5);
 ^
/Users/jorgevega/Documents/Arduino/LecturaBloqTags_RFID/LecturaBloqTags_RFID.ino: In function 'void setup()':
LecturaBloqTags_RFID:8: error: 'rfid' was not declared in this scope
  SPI.begin(); rfid.init(); 
               ^
/Users/jorgevega/Documents/Arduino/LecturaBloqTags_RFID/LecturaBloqTags_RFID.ino: In function 'void loop()':
LecturaBloqTags_RFID:17: error: 'rfid' was not declared in this scope
  if (rfid.isCard()) {
      ^
LecturaBloqTags_RFID:22: error: 'rfid' was not declared in this scope
  rfid.halt();
  ^
exit status 1
'RFID' does not name a type

What can be? I believe that I know how to add a library perfectly, but will never know… Can someone help me? Thanks for all.

PD: In the code, RFID made reference to this library: GitHub - pkourany/RC522_RFID: RC522_RFID library ported to Spark Core with added support for Software SPI

What can be?

How is the compiler supposed to know what an RFID is?

PD: In the code, RFID made reference to this library

Did you download and properly install that library? The compiler doesn't think you did.