Sequence and structure of booting system & processing

Hello Experts! I have some questions regarding the sequence and structure of booting system and its process. My questions are:
While the system boots up, I want to know about the IDs connected with the process. I want to know the Fork() System Calls in creating a process. Also, can you please list down the system calls that is used in process management? How does the parent and the child process communicate with each other? What are the UNIX process states and what will happen if I run a program and a command? Thanks in advance.
