Hi,
I need help to understand a piece of the code i'm using in my school project. Here is the code, but i need help to understand how the void loop is working, and how i can get information in my serial monitor when the switch it is on and off?
Hope someone can give me a answer 
// Relay control using the ESP8266 WiFi chip
// Import required libraries
#include <ESP8266WiFi.h>
#include <aREST.h>
#include <aREST_UI.h> // Biblotek som lager on/off knappene på mobilen
// Create aREST instance
aREST_UI rest = aREST_UI();
// WiFi parameters
const char* ssid = "kjetil sin iPhone";
const char* password = "12345678";
// The port to listen for incoming TCP connections
#define LISTEN_PORT 80
// Create an instance of the server
WiFiServer server(LISTEN_PORT);
void setup(void)
{
// Start Serial
Serial.begin(115200);
// Create UI
rest.title("Relay Control");
rest.button(5);
// Give name and ID to device
rest.set_id("1");
rest.set_name("esp8266");
// Connect to WiFi
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
// Start the server
server.begin();
Serial.println("Server started");
// Print the IP address
Serial.println(WiFi.localIP());
}
void loop() {
// Handle REST calls
WiFiClient client = server.available();
if (!client) {
return;
}
while (!client.available()) {
delay(1);
}
rest.handle(client);
}