Download and install the Arduino IDE from the official web site.

1 - In your Arduino IDE, go to File> Preferences

 

2- Enter https://dl.espressif.com/dl/package_esp32_index.json into the “Additional Board Manager URLs” field as shown in the figure below. Then, click the “OK” button:

 

 

3- Open the Boards Manager. Go to Tools > Board > Boards Manager…

 

 

4- Search for ESP32 and press install button for the “ESP32 by Espressif Systems“:

 

 

5- That’s it. It should be installed after a few seconds.

 

 

6- In Tools > Board menu select the DOIT ESP32 DEVKIT V1 board:

 

 

7- Select the Port (if you don’t see the COM Port in your Arduino IDE, you need to install the CP210x USB to UART Bridge VCP Drivers):

 

 

8- Test your installation open the example under File > Examples > WiFi (ESP32) > WiFiScan

 

 

9- upload the code with the button . After few seconds you have to press the BOOT button on the board to complete the upload.

 

10- Open the Arduino IDE Serial Monitor at a baud rate of 115200. You should see the networks available near your ESP32:

 

 

In the Arduino IDE open the menu Sketch->Include Library->Manage Libraries and search the WebSockets library by Markus Sattler  (see the picture below)

 

 

Select the library then click on Install button.