Get proper training
The most important thing is to get proper training from a professional, as you will then be aware of the basics of playing a piano. You can get various tutorials on the internet, but it is better hiring someone in order to become an expert.
Select your favourite song
Once you are aware of the technicalities, choose your favourite song, and follow the chords used in it. There will be quite a few songs of your choice, but try starting with the easiest one.
After you have the notes in front of you, start playing them slowly. Don’t get ahead of yourself, as you will take some time to perfect this art. Patience is the key in this process.
Practice one song repeatedly
You will make a few mistakes in the first go, so don’t be worried about it. Continue practicing over and over again in order to achieve perfection, and eventually you will definitely see a clear change in your skills.