You could make a script like this:
#!/bin/bash

if [$# -ne 1 ]
then
echo -e "\n\tSyntax: $0 {start | stop}\n"; exit 1
fi

case "$1" in
start) {{{{{INSERT HERE COMMAND TO START}}}}
;;
stop) {{{{{INSERT HERE COMMAND TO START}}}}
;;
*) echo -e "\n\tSyntax: $0 {start | stop}\n"
;;
esac


exit 0


You'll call this file, let's say, samba and put it in /etc/init.d

Now, go to /etc/rc3.d and make a symbolic link to the file you just created, like this:
cd /etc/rc3.d
ln -s /etc/init.d/samba S99samba


And finally, repeat those links in /etc/rc5.d
cd /etc/rc5.d
ln -s /etc/init.d/samba S99samba


Now, each time you start your system, it should execute the samba daemon