I hope you are doing well.
I have a project which is Rotary car parking. I want to use a keypad, LCD screen, and stepper motor to create it. I need some help with the programming part.
I want to create a system to park a car and give it a code then call back the car by this code.
Full size cars? With one stepper motor?
If programming is the difficult part, then leave that to last. Get the mechanics working. Yes, you will need an Arduino to drive the stepper motor but it should not be hard to use one of the Stepper examples to make it move for the purposes of testing.
So all you need to do is first learn how to program a keypad and an LCD display and a stepper motor. There are plenty of example programs to help you with all of those.
Then put together a detailed specification saying things like exactly what has to be entered on the keypad and displayed on the LCD and exactly how and when the motor has to move. Then you can write your first attempt at the complete program and post it here together with details of exactly what components you are using.
And if it isn't quite right first time then we'll be glad to help you to get it working.
These links may help with the stepper motor part
Stepper Motor Basics
Simple Stepper Code
And you may get some general ideas from this
Planning and Implementing a Program