Congratz on your first lucid dream I guess TwilightShawn and Dragonmaster21 have already answered your questions very well, but I might as well try and say something... Even though I'm just a newbie. ^^

1. Lucid dreaming & controling your dream are not the same things. You can be lucid, but not able to control anything. I had my first lucid dreams this night as well, and it was very hard to control stuff. In the second dream it was already easier... So controling is, I guess, just a matter of practice. There also degrees in how lucid you actually are, and you don't stay lucid all the time... Complicated!

2. As the others said, the guy might have been your dream-guide. But I think (personally) that's also important to keep in mind that dreams are created by your subconscience. So I think dreamguides or dream characters telling you stuff about your dream are actually your own subconscience, telling you what you know about dreams. This night, in my lucid dream, before I flew through the window, I asked my mother (in my dream!) whether I could fly through the window. She answered: "Of course you can, but there is a price to pay." (She meant good nightrest and my health, she's kinda against lucid dreaming). When I tried to fly through, but failed, she told me that I should remember to be very convinced that it would work. I'm sure she was actually just an expression of my knowledge of lucid dreaming. Maybe the dreamguy telling you dreamstuff was the same sort of thing?

3. My RC's failed as well. But I manipulated my dreams in such a way that the RC's had the proper result. I grew an extra finger and manipulated my mirror reflection. Later in the dream, I crossed another mirror... And this time, my head was gone without I had to manipulate it. It was bizarre, creepy and awesome at the same time. So maybe you should try to manipulate the RC's in your next dream?

Again congratulations, and I hope my newbie-knowledge was of any use to you... But again, I'm just a newbie and these are just my thoughts on your dream, not saying it's an infallible answer. Good luck with your next lucid dream!