what are the steps to activate it??

thanks

http://fallout.wikia.com/wiki/Old_School_Ghoul

Make sure you save before you talk to the final person (Loyal, in my case). In my first time of playing with Raul as a companion, he had the conversation regarding Loyal but then didn't follow up with the talk that leads to him deciding what to do with himself (and thus gaining a perk). Worked the second time, though.

well he talked to me but no quest came up..

i this the type of quest i just got to go by what he says, with not "side quest" in the quests in the pipboy

It's an unmarked quest, so it won't be in your Pipboy, no.
Once you've spoken to the three individuals, Raul should say something about going back to his gunslinging ways (or not as the case may be) and you can agree or talk him out of it. He'll then either get a cool vaquero costume or will remain a repair specialist, depending on your choice. If that part of the conversation doesn't come up, however, you'll need to reload and talk to the last person again (make sure you have a save point before then).