I am glad that you liked the rendition.
It took basically 3 months to do this, although I had started on it 15 years ago :)
About learning this: is not too difficult. Garritan Personal Orchestra 4 is easy to use - the sounds are just embedded as a VST synth within Sonar.
Sonar is a bot more complex. but adding, recording, and editing the MIDI tracks is no big deal. I usually play each track live from the score sheet (so you need to be able to read music and understand the proper transpositions etc.), then I add the "expression" with a wheel after the note recording. Finally at the end I draw the tempo map. Is largely "try and error".