Getting started with NodeMCU using Arduino IDE

The ESP8266 community provided us with an extension of Arduino IDE, it allows us to program in C with ESP8266. This makes things easy for the arduino developer. This tutorial helps you on how to install the ESP8266 boards. Before going into the installation. You should have an Arduino IDE installed, if not click on this official Arduino site.
Steps to be followed for the installation:
1. Go to your Arduino IDE, File->Preferences.

2. Enter “http://arduino.esp8266.com/stable/package_esp8266com_index.json” in the Additional Board’s Manager URLs. The above link install’s all the ESP8266 boards. If you want to install the esp32 boards. Then place comma(“,”) in between the links and paste it into the additional boards manager.The link for esp32 board installation is https://dl.espressif.com/dl/package_esp32_index.json.

After pasting the links, click “ok” which is in below. Generally we install the boards from the board manager.
3. Now, open the boards manager as shown in the figure.

4. Now, search for ESP8266 and click on the install button for “ESP8266 by ESP8266 Community”.

5. The board is installed in Arduino IDE and ready to be used.
Sample Program to Test:
If you're using ESP-12E NodeMCU kit, upload this sketch/program into your microcontroller for testing. Connect your board to the Desktop/laptop using the cable. Now make sure you have selected the NodeMCU 12E board.

Select the appropriate “Port”, in my case it is “COM3”

Now, upload the below code for the testing of the board:
/*
Check out http://theroboticsclubsnist.org/ for more tutorials. */
void setup() {
pinMode(LED_BUILTIN, OUTPUT); // Initialize the LED_BUILTIN pin as an output
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(LED_BUILTIN, LOW); // Turn the LED on (Note that LOW is the voltage level but actually the LED is on;
//this is because it is active low on the ESP-01)
delay(1000); // Wait for a second
digitalWrite(LED_BUILTIN, HIGH); // Turn the LED off by making the voltage HIGH
delay(2000); // Wait for two seconds (to demonstrate the active low LED)