Cormac hi
I'm John.
Generally the recommended reading would be the Trevor Thom series of manuals from the "official learning" point of view.I think thats all would need, no real need to go beyond that, however if you feel you may struggle and would like the assistance of some DVD's then go ahead but do note that most DVD's you see online are based on america so american differences can pop into your trainning not that they are going to be big changes but be aware of it.
I use MS for,
1.becoming somewhat familiar with the jargon from the reading material in the sim lessons
2.For practising navigation its fine of course.
3.I use also for practising a little flying (eg flying circuits in the cessna, where would I be making radio calls at what points, starting descents etc etc, just to get your brain used to a flow). Although I am informed flying in FS and flying the "beast" herself are two different things.
FS can have its uses if applied properly.
Hope thats of some help to you.
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regards
John