I used LED_BUILTIN, which is 2 in most esp32 modules, including wroom. Wroom has two LEDs on board. The red led is power. The blue led is 2. You should see blue led lights up.
I know that the ESP32 has red and blue LEDs. What I want to do is to light up an LED that I have newly connected. I believe that LED_BUILTIN refers to the blue LED built into the ESP32, is that correct?