How to make a simple ESP32 Wifi network scanner

// Heltech WiFi Kit 32 Wifi Scanner
 
#include "WiFi.h"
#include <U8g2lib.h>
 
U8G2_SSD1306_128X64_NONAME_F_HW_I2C   u8g2(U8G2_R0, 16, 15, 4);
 
void setup()
{
  WiFi.mode(WIFI_STA);
  // Initialize the graphics library.
  u8g2.begin();
  u8g2.setFont(u8g2_font_6x10_tf);
  u8g2.setFontRefHeightExtendedText();
  u8g2.setDrawColor(1);
  u8g2.setFontPosTop();
  u8g2.setFontDirection(0);
}
 
void  loop()
{ 
    int nNetworkCount = WiFi.scanNetworks();
    u8g2.clearBuffer();
    // Display networks.    
    if(nNetworkCount == 0) 
    {
        // No networks found.
        u8g2.drawStr(0, 0, "0 networks found.");
    } 
    else 
    {
 
        char    chBuffer[128];
        char    chEncryption[64];
        char    chRSSI[64];
        char    chSSID[64];
 
        sprintf(chBuffer, "%d networks found:", nNetworkCount);
        u8g2.drawStr(0, 0, chBuffer);
 
        for(int nNetwork = 0; nNetwork < nNetworkCount; nNetwork ++) 
        {
            // Obtain ssid for this network.
            WiFi.SSID(nNetwork).toCharArray(chSSID, 64);
            sprintf(chRSSI, "(%d)", WiFi.RSSI(nNetwork));
            sprintf(chEncryption, "%s", WiFi.encryptionType(nNetwork) == WIFI_AUTH_OPEN ? " ": "*");
            sprintf(chBuffer, "%d: %s %s %s", nNetwork + 1, chSSID, chRSSI, chEncryption);
            u8g2.drawStr(0, 8 + ((nNetwork + 1) * 8), chBuffer);
        }
    }
 
  u8g2.sendBuffer();
  delay(2000);
}