You need to figure out the steps needed for that and then ask a specific question about a step you need help with. For example, if I was making a calculator, I might have these steps:
Display 0
User presses a number button
Display number value
User presses an operator button
User presses a number button
User presses equals button
Calculate answer
Display answer
And I might ask a question about how to do step #3.
Start building the project with buttons, labels, etc. and share your progress. If you ask a really broad question, it’s hard to help you!