First you need to put the ESP32Cam into flash mode, by connecting the GPIO0 pin to GND, then connect the USB to Serial adapter as shown in the image below. Now connect the USB Serial adapter to your computer.

The in CodeSkool Board menu, choose Upload Firmware submenu.

Click connect and then choose the correct COM serial port associated with the ESP32Cam. Once connected click the Program button to flash the firmware.

It will start the flashing process, and will take few minutes to complete the process.

Once the flashing is done, close the dialog and disconnect ESP32Cam. Then remove the wire connecting GPIO0 to GND, and reconnect the power to ESP32Cam. It will start a WiFi endpoint with SSID name starting with “tasmota” and some random digits at the end.

Connect to the “tasmota” open WiFi and enter your network WiFi credentials in the web page that get launched and click the Save button.

Once the ESP32Cam is connected to your WiFi network, it will show you the same with the IP address of the ESP32Cam.

Open the IP address in your browser and verify that the ESP32Cam is working properly. You still can’t connect to this IP address from CodeSkool, as its runs on SSL and the ESP32Cam server is not secure.
You can use tools like ngrok to act as a SSL proxy to your ESP32Cam. Go to https://dashboard.ngrok.com/get-started/setup/windows and install the ngrok tool.
You also need to get the auth token from: https://dashboard.ngrok.com/get-started/your-authtoken
Now run the command in the command prompt, while replacing with your actual token in the command
ngrok config add-authtoken $YOUR_AUTHTOKEN
Then just run the below mentioned command, replacing $ESP32CAM_IP with your ESP32Cam IP address.
ngrok http $ESP32CAM_IP:81
It will proxy the port 81 and provide you with some SSL forwarding URL to the ESP32Cam. Something like as shown below:
Forwarding https://44e8-152-58-210-24.ngrok-free.app -> http://192.168.32.153:81
Now load the ESP32 Cam extension in CodeSkool and provide your stream URL

If you are using your own ESP32Cam firmware, you need to use the following commands to avoid the CORS error:
ngrok http 192.168.32.153:81 --response-header-add "Access-Control-Allow-Origin: *"
Remember the forwarding port is 81, and the url path is /stream