run script at startup

I am using AIX 5.3 in P6 machine.
I have a script "test.sh", when i run it manually it runs properly.
I want to run the script automatically when system starts.
I kept the script in /etc/rc.d/init.d and also in /etc/rc.d/rc2.d but it is not working.
Do i have to write it in inittab instead of keeping it in rc.d?
how can i write it in inittab file

thanks

while you could edit /etc/inittab manually using the mkitab command is the proper way. Read the manpage and you will get the picture:
$ man mkitab