One question, first:
What are the fundamental parts of music?
Look it up, if you have the time...or interest.
If I may be so bold? Blunt? Whatever, not trying to sound cocky here...
Start with:
'Copland, Aaron (1939; Revised 1957), What to Listen For in Music'
My opinion:
'Classical' music is
complex, dynamic, expresses a story without a single lyric.
So many patterns. Changing, flowing...
Also, thee are many kinds of classical music. So...