I am having difficulties figuring out how to code and understanding it all
Don't jump in and try to do it all at once. Try the examples in the IDE.
Read an input and output a message when the input goes HIGH or LOW
Read an input and change the state of an output to match the input. The LED on pin 13 is good for this.
Read several inputs and print a message indicating which one changed state
Read several inputs and turn on a different LED depending on which input changed state.
Small steps towards your final project