How to use LCD Screen and IR Remote to broadcast a countdown
How do I do this?

I have no clue how you do that but I do know I would do that.

I know how to ask a question.

Apparently not, your question is far from perfect (and my answer above is technically the only correct answer to that specific question). It doesn't tell us what you've tried, it doesn't tell us what you haven't tried. It not specific nor practical. Doesn't state your experience with Arduino, doesn't state which hardware you (would) be using. (Though I must say your example output thing is quite nice)

I was just in a rush.

Isn't everyone nowadays? And why would we invest time in an answer on a question which has no effort put into it?

You're basically asking &quot;How to do an Arduino project&quot; (or any project), there's many ways but let's dive into it.
0. Split up your project into smaller projects.
Since it sounds as if you have no clue on how to get started or if you feel this project is daunting, it may help to make the 'problem' easier to get started. You can always add more complexity.
Make one Arduino program, which shows &quot;Hello World&quot; on the LCD.
Make one Arduino program, which receives IR codes and depending on which button pressed, shows &quot;Hello&quot; or &quot;World&quot; in your terminal.
1. Research
Search the internet, maybe there's projects like this. Try to google for &quot;Arduino Countdown Timer&quot;. Check what design choices they made, what hardware they use and how they work in general.
2. Design
Make a design, not only about the aesthetic part, but also functionally. What happens if the timer depletes? Should it also have a buzzer? Does it need an enclosure?
And technically, how will it be powered?
3. Acquire hardware
As a starter; it can help to buy hardware from stores that also include example code.
Use the example code to test and verify your hardware and connections.
4. Software
If you're asking &quot;How to write software&quot;, you're better off starting out with some example projects/tutorials which include the code and explain it.
But basically you should use the example code to drive the hardware, use examples on the internet combined with your own experience to create a program that matches your required behavior.

If, along this path, you have a practical question. We will be much more able to, and happy to, help.