I don't know of an idiots guide as such. Flying a plane is like driving a car, its easy once you've learnt the basics and practiced it. You have the advantage of using a simulator, so if you make a 'pig's ear' of it, no damage is done, apart from your pride.
You need to understand the basics of flying to get the best out of any of the simulator programs, to do that there are a number of flight training manuals to help, Pooleys is a well reconised one which I use click here. This will take you from step one, how all the controls work, how the flaps work, right through to how all the navigational devices work and how to use them and to understand how the aerodynamics work to stop the plane immitating a brick!
The best advice is to pick a simple plane, maybe pick a local airfield to you that you've seen and try doing circuits and bumps, that is taking off then doing a racetrack pattern and landing. You'll find you'll keep crashing, that doesn't matter, you'll find after a period of time the crashes will get less and you'll start to fly further. Don't worry about crashing, frustrating, but no harm.
I have been flying for years now, when I first started, I couldn't even get off the ground without help, now I can handle the big multi-engined planes with ease, including all the nav-aids.
Good luck, and happy flying!