pro2105p 0 Newbie Poster

Hi, I am new in OS programming and I need some links for newbie OS programming.
With detailed explanation of syscalls (I don’t ask for ready code , just explanation and some example code if exist )
I try google but I didn’t found match things (nothing for a newbie anyway)
My project is to make a multiprocessing (unix) kernel in c . I must make exec , exit ,
Mutex_lock-unlock , con_wait ,con_signal …….
He gave use some code for contex and signals but it just got me more confused (and the code needs some changes)
Tnx in advanced for ur help