/etc/rc0.d is the area used when shutting down the server
/etc/rc2.d is the area used on bootup


All you need to do, is to add you script in the /etc/rc2.d area.
lets say you call the scripts S98start

On bootup it will read your start and start whatever you are planning to run

then to stop whatever you have started (if needed) you can then create another script called /etc/rc0.d/K98stop todo the reverse of S98start.

i hope makes sense.