Hey guys...!! I m pretty new to Linux..!!

I've been given a task to modify network protocol(TCP in particular). So now i've to make few changes to the kernel which includes modifying few source files. So i want to know how can i go abt it. Till now i've explored various .c files of kernel(Eg.tcp.c,tcp_input.c etc etc)by referring few books. And now comes the important part of implementing it. So how exactly can i go abt it?? I went thru various threads like installing a kernel,compliling a kernel and other things. But i m not getting the exact sequence in which i should do it. I've installed fedora 10. But i cannot see any source files which i can modify. Where and how can i modify these files???Any form of suggestion will be of g8 help for a newbie like me... Thanks in advance..