What I essentially want to do is, I want use log/print statement somewhere in the source code to get to know about its flow. I also want to do this debugging while running blender on the other side.
I have never used a debugger before. But I want to contribute to Blender. So at this point all I am doing is reading GDB and VS-code’s documentations.
All this might sound totally newbie, because I am a newbie. Any help or reference will be appreciated.
I’m in the same boat. I can build on Windows but i cannot understand how to help.
Perhaps you would try to use C++ Visual Studio 2019 here because it would be much better in terms of compatibility and stability on Windows. Only a simple account login is needed and you can use it without any cost.
I have noticed that MinGW compilations are not smooth, at times result into unexpected fails and it just adds up more troubleshooting.
Then you can find for tutorials etc, how to build things:
I am searching for videos and docs too,yesterday i found this old blender bugfixing video.
Hey guys do you know any books about rendering algorithms, math for computer graphics, 3d concepts and Proficient in C/C++? 
Yesterday i tried to debbug with vscode but i can´t do it on windows 
but i will use visual studio for read the code and today i will try fix some bug.
Graphics algorithms are pure math, so is either you don’t understand anything or otherwise learn everything mechanically by heart. You can check things like [raytracer] or [software renderer]. However you might start with Python or Java there because all C++ solutions tend to stick to optimization techniques and add more burden to the code. Your point here is only educational value.
https://www.youtube.com/results?search_query=how+to+write+raytracer
Also for C++ you could get Stroustrup’s book or any other that explains language concepts in detail. However these books are really good for technical reference. Of the best books I ever read for C++ was only one based on Financial programming. You can skip entirely the financial calculations and focus only on language features such as classes, shared pointers, inheritance, etc.
https://github.com/Apress/practical-cpp-financial-programming