LED's not lighting up

A useful exercise for debugging is just to personally play the part of the processor. Take out a piece of paper to serve as your "memory" and start by writing down the initial states of your global variables. Then step through your code one line at a time thinking about what happens at each line and updating the values on the paper as necessary. Just be careful to pay attention to what the line of code actually says, and not what you meant it to say or what you think it should mean.

Delta_G:
A useful exercise for debugging is just to personally play the part of the processor. Take out a piece of paper to serve as your "memory" and start by writing down the initial states of your global variables. Then step through your code one line at a time thinking about what happens at each line and updating the values on the paper as necessary. Just be careful to pay attention to what the line of code actually says, and not what you meant it to say or what you think it should mean.

VERY useful indeed! I feel like I did a step similar to that, but not as in depth, so I will definitely will try that to stay a little more organized and detail oriented in upcoming projects! Thank you!

When you read code in your IDE or online, keep a browser tab open to the Arduino Reference page.
https://www.arduino.cc/reference/en/
Look up what you don't completely know and after a few times you will know it enough to use it.

These are arrays, a very basic part of C/C++/Arduino;

const byte ledPin[ 3 ] = { 2, 3, 4 };  // ledPin[0] == 2, ledPin[1] == 3, ledPin[2] == 4

const char ledColor[ 3 ][] = { "red", "green", "blue" };  // ledColor[0] == "red", etc

With arrays you can refer to variables by index. The led pins could be 8, 3, 11 and still ledPin[0] would be the red led pin.

    Serial.print( F( "You chose the " ));
    Serial.print( ledColor[ colorChoice ] );
    Serial.print( F( " led." ));

Where colorChoice is 0 to 2.