Read value from KY018 Sensor and calculate lux

Hi, today i received my new analog light sensors (KY018) to put on my weather station. I search here how to convert a analog value to LUX and found this

Here they have in mind the resistor between the LRD and the reading pin, i'm an informatics not electronics so i bought this al in one package.
The KY018 as a resistor (i think) that says 103, search about that on google and the resistance is 10K Ohms, i not seams work when i run the programs based on this Lux - Wikipedia
At dark it gives the read values of 869 and 0.28 Lux, when i aim the flashlight to the sensor i get read value of 59 and 0.00 lux
here is my code

void readLight(){
  int AR=analogRead(PHOTOPIN);
  Serial.print("AR: ");
  float Vread = (AR * 0.0048828125);
  float RLDR = (10000.0 * (5 - Vread))/Vread;   
  lightLevel = (500.0 / RLDR);
  Serial.print("Lux: ");