Hi Jonathan,
I have picked up a few things about music theory, like how scales are constructed from their intervals, some progressions and how to assemble some chords - especially triads. But other than that I don’t really have a clue. Most of the stuff I have written has been more by luck than design.
In terms of instruments, I can just about play the guitar, but alas that’s it.
I have always been fascinated with Orchestras - though I have never seen one in real life (that is on my to do list). One of my favourites to listen to is Beethoven’s 9th - the 1st movement. There is something very magical the way it starts from almost nothing then works its way into a titanic struggle!
Presumably by orchestration you mean which instruments to use and when?
Sorry about my noobness 
RobP