Are there any tutorial for working with the source code?

I've gone through the wiki tutorial for Compiling FileZilla 3 under Windows https://wiki.filezilla-project.org/Compiling_FileZilla_3_under_Windows

and have successfully built FileZilla. I'd now like to start digging into the source code, but I'm pretty much lost. I do have a little bit of experience with C++ but not much. Could I get some tips on how/where to get started? For example where is main() ?

Thanks for any help,
Barry