Howto automatic run/start a program at startup?

I'm using Mageia 2 x86-64.
When I start the computer I whish to run a program automatic (no need to do any manual action).
I have found out that I have to put the command in one of the directory /etc/rc0.d - /etc/rc5.d.
rc6.d looks like to be used when shutdown the computer.
I think the commandname has to begin with Snumber. The command with the highest number will start last.
I have looked in both rc3.d and rc5.d.
In rc3.d, rc4.d and rc5.d there are a some commands that already start with S99.
First: Can I have my startcommand beginning with S99?
Second: In which directory?
When I start the computer I whish to run a program automatic (no need to do any manual action).
I have found out that I have to put the command in one of the directory /etc/rc0.d - /etc/rc5.d.
rc6.d looks like to be used when shutdown the computer.
I think the commandname has to begin with Snumber. The command with the highest number will start last.
I have looked in both rc3.d and rc5.d.
In rc3.d, rc4.d and rc5.d there are a some commands that already start with S99.
First: Can I have my startcommand beginning with S99?
Second: In which directory?