How to show graph while detecting pulse

I am really noob at this

Then the first thing to do is study the tutorial section and repeat the sketches there, change them and see what it does. That will learn you (and in fact everyone) so much about the how things are done in Arduino. You will recognize several tutorials that implement part of what you need, an dthen the only thing you need to do is combine them. But first go through many of them, and if you don't have the electronics to implement/do a sketch try to understand how the code does its job.

If there are questions or you need some explanation, just ask.