Changing a variable in code with a button and display it on an LCD?

Hi guys,

Total noob here, so sorry for stupid questions.

Basically, I have this code. It's a modification on the Easy Driver code, and I want to be able to change ____ , _____ and ____ with a button, and for whatever is selected to be displayed on an LCD.

Here is the code

int dirpin = 2;
int steppin = 3;
int TimerPin = 13;




void setup() 
{
pinMode(dirpin, OUTPUT);
pinMode(steppin, OUTPUT);
pinMode(TimerPin, OUTPUT);
}
void loop()
{

  int i;

  digitalWrite(dirpin, HIGH);     // Set the direction. LOW = to motor, HIGH = away
  delay(100);


  for (i = 0; i<50; i++)         //  DISTANCE PER LOOP
  {
    digitalWrite(steppin, LOW);  // This LOW to HIGH change is what creates the
    digitalWrite(steppin, HIGH); // "Rising Edge" so the easydriver knows to when to step.
    delayMicroseconds(8000);     //Speed- Seems to be max of 8000
  }

  
    delay(2000);    //pause between stopping and shooting
    digitalWrite(TimerPin, HIGH);
    delay(15000);    //exposure time
    digitalWrite(TimerPin, LOW);
    delay(2000);    //pause before moving again

}

I want to be able to change

digitalWrite(dirpin, HIGH);    // Set the direction. LOW = to motor, HIGH = away. I want to change the HIGH to either HIGH or LOW.

,

 for (i = 0; i<50; i++)         //  DISTANCE PER LOOP. I want to change the 50 to one of say 5 options

and

   delay(15000);    //exposure time. I want to change the 15000 to one of say 10 options.

without having to plug into my laptop every time. I'm guessing I need a way to "start" and "stop" the loop after I've changed these?

I would like to have button1 cycle through the 3 things I want to change, button2 to cycle through the lets say 10 options for each thing, and then button3 to start the program in a loop.

Again, sorry for asking so much. If you could give me a good place to start, some basic code, or just some way to set me on the right path, I would really appreciate it. Please dumb it down as best you can.

Thanks so much,
Jesse.

Do you know how to read the state of an input pin ?