how to read multifiles sourcecode like games engines

hello
i am good in c++ and oop but when i downloaded some open source programs from sourceforge (game engine or an emulator) i didn't understand the code because there is many .h files,classes,functions,namespaces.
please give me some advice to get familier with the sourcecode and how to know the way and style of the programmer.
thanks

Start reading the code. Use "find in files" feature of your IDE (if you have one). Or use something like Understand for easy code navigation. Or you could setup LXR to navigate through the code.

gg