First, install iTunes on your PC. After that follow the steps below.

Connect your iPhone11 to your PC via Lightning to USB cable.
Quickly press and release Volume Up button.
Quickly press and release Volume Down button.
Press and hold the Side button for 5 seconds until iPhone’s display turns black.
While continuing to hold the Side button, press and hold Volume Down button for 5 seconds, and then release the Side button while you continue holding Volume Down button for another 10 seconds. If these steps are performed correctly, display should remain black with no text or logos on it.
Open iTunes on your Mac or PC, and you should see a message saying that “iTunes has detected an iPhone in recovery mode. You must restore this iPhone before it can be used with iTunes.” You’ll then be offered an option to restore iOS on your iPhone.
If Apple logo appears, the Side button was held down for too long. Repeat the process again.

If the restore fail, then it is hardware problem, may cost few hundreds to repair.

thanks for the detail steps. the phone is not with me now, will try when i have the phone. thanks alot!

the shop reserved the phone for me but i havent go to collect the phone yet as i m out for raya holidays hahahaha

ahhh nice! selamat hari raya to you and family too!
have a great one and be safe!