As a newbie at this, I had to figure why I was getting a “redefinition of ‘const int ledPin'” error when I tried to compile your ESP32 Course Blink_LED.ino file. If you open a “.ino” file with the Arduino IDE in a directory that as multiple “.ino” files in it, then the Arduino IDE will open all of the “.ino” files in that directory and compile them. The “Blink_LED” master course subdirectory has a “Blink_LED.ino” and a “Blink_LED_PlatformIO.ino”. Both files have the line “const int ledPin = 23;”. Because the Arduino IDE “automatically” attempts to compile all “.ino” files in the directory you will get the “redefinition of ‘const int ledPin'” error. Even though it was a good lesson in and of itself for me (Arduino IDE quarks), in a course like this, newbies like me should not be having to work through this sort of issue for the very first sample project component hookup project in the course when the solution is simply for the course owner to delete the “Blink_LED_PlatformIO.ino” file or move it into it’s own separate sub-directory.