I don't know why the answer below is accepted, as it clearly doesn't solve the question but also gives false information. In this answer @chrisl assumed that blinking green LED is what was programmed with sketch, but if you will open sketch used in this video and read comments in the source code, then this misconception will become obvious: actually red RX ...
َAbout first question I found after AT command AT+CWJAP="network","password" it takes a while to have active and ready wifi connection , so I used a 30 seconds delay after this command and then send sensor data toward thingspeak.com , now problem is solved .
You are obviously currently programming the ESP8266, not the Atmega328p. The board seems to have DIP switches on it. With those you can control, which chip is connected to which. The product description has the following table
1 2 3 4 5 6 7
ATmega328<->ESP8266 ON ON OFF OFF OFF OFF OFF
There's an official Telnet-to-Serial example on Espressif's Arduino GitHub repository. It shows how to set up an ESP32 to act as a serial (over USB if your board has it) to WiFI (using telnet).
Hopefully this is something that will help you get along.
The WiFiManger's autoConnect function starts the configuration web server (and AP) only if connection to configured WiFi network is not established.
If you want to run the WiFiManger's web server to reconfigure WiFi or to set other parameters, you can start the WM web server with the startConfigPortal function.
autoConnect and startConfigPortal are blocking ...