Most women do not have an orgasm from intercourse alone - usually some sort of stimulation of the clitoris is required.
The best position is a matter of personal preference.
You'll know if you have an orgasm because your body will shudder all over, centered in the pubic area, and it'll feel really good. Then you'll feel relieved and relaxed. I've read that one sure way to know that a woman has had an orgasm is that her nipples will be erect, and it seems to hold true.
Three minutes is a little short. He's probably really excited and hasn't learned how to delay his response. This takes a little practice, I believe.
Masturbation will absolutely help you learn your body and what you respond to, and will help you get the most out of your relationship with your husband. I hope there is a place in your faith for this. Married women do masturbate, and it can make things more exciting for both of you.
Try thinking about sex, whatever gets your interest, then imagining your husband touching you. Close your eyes and try doing what you would like him to. Experiment and see what feels good. As for setting the mood, I usually would not do this but if it helps, go ahead! Nothing wrong with that. Maybe taking a nice bath first will set the stage and help you relax. Basically you need to be thinking about sex first - otherwise you won't be in the right mood. As for what that consists of, it's another one of those individual things.
When I was a little girl, one of my friends showed me how to masturbate. I had never even thought of it before then. She showed me that she scratched herself with her finger outside her underwear. That's how I got started, although I progressed from that point.
I don't think it's dumb to ask questions. It would be dumber to never explore any further and just be satisfied with whatever, in my opinion. I'd say you should maybe seek out some reading material, that way you don't have to ask someone in person.