Hi guys, I really want to start fixing bugs, but Blender is so big, that when I go to find some bug to fix on the bug tracker, I don’t know where to start, I mean, where exist this bug, on what area of the all lines of the code ?
If someone with a good experience at that, made a tutorial, explain and give some tips of how to find bug at the code, will be of great help 
Sorry to tell you that, but part of fixing bugs is to track down the code that causes it. If you are unable to locate the relevant lines, you’re certainly not the right person to fix bugs.
Two tutorials by ideasman: