@Rick_Maity as others have pointed-out, we don’t teach basic C++ programming here, and it appears that’s what you need to learn.
A few hours of watching Youtube videos, or doing online tutorials, followed by a few more hours of experimentation should get you to the point where you’re ready to start answering your own questions.
The Blynk Sketch Builder thatI linked to earlier is a great resource and one that you should use to help you learn how to structure code so that it works well with Blynk.
When you’ve done your ‘apprenticeship’ in C++ then the questions you ask will be more focussed, and you’ll have a better understanding of the answers that you are given. Until you get to that point it’s difficult to help your to help yourself.