I’ve seen the transcribing of other people’s music recommended many times as a way to learn the art of orchestration and composition. The idea is to get a recording of a classical piece of music, attempt to recreate it by listening to it, performing the parts you hear into your DAW and then checking the actual conductor’s score to correct any mistakes. Doing this for a while will help to recognize patterns and be able to re-use those patterns to compose our own music.
There are places that sell conductor’s scores but I’ve found another interesting (free) way. Some live composing videos on YouTube are detailed enough that you can see exactly what is being recorded, by seeing the composer’s hands on a piano as they record a track, or seeing the piano roll in enough detail to figure out exactly what notes were recorded.
I would recommend performing a YouTube search for “live composing”. This will lead you to videos of composers as they work on a new piece of music. You can see step by step exactly how they do it.
Here are some of those videos (if you’re interested in epic/trailer style music):
In the video description of the following video, you will find a link where you can actually download the audio of individual tracks and the MIDI as well. If you become a patreon (paid subscriber) of Alex Moukala, you will be able to download the audio tracks and MIDI of many of his compositions for studying purposes.
Thor: The Dark World’s Theme – by Alex Moukala
In the following video, by carefully watching his hands, you should be able to figure out exactly what is being played so you can create your own version for studying.
CineSymphony LITE Composition Screencast – by Michael Patti
Plus,
https://www.youtube.com/watch?v=KWycfHqnU6E&t=603s
How I make EPIC CINEMATIC MUSIC – bY Olexandr Ignatov
And finally: