@komalkristina
You really should start a new thread for this since you don't appear to be using a 20x4 display.
Here are some things to include in your new thread:
Did your display work correctly for something simple like the 'Hello world' sketch?
What do you expect to appear on your display and what do you actually see on the display?
Also - Highlight the portion of your post that is program code and then use the 'Code' button, which looks like --> #.
Don