easy g++ question

hi, i'm a total beginner in Linux so this might be easy:

i have a cpp file that includes 3 h files
src.cpp
header1.h
header2.h
header3.h
and i would like to compile them into a library (a .so file). g++ is very complicated to me - a simple windows guy :)
can you please tell me exactly the commands i need to type in ?

thanks