Go to the symphony. Ideally, go with a friend who enjoys classical music.

Also, spend some time trying different classical music from different periods / parts of the world. You might find you prefer Steve Reich (Music For 18 Musicians) more than you like Bach (Well-Tempered Clavier) or Shostakovich (10th Symphony) more than you like Schoenberg (... good luck).

Spend some time finding a favourite composer. Start with a composer you like, and then try other composers who were alive in the same time and place.

Also, beware of orchestral renditions of pop music. Some of it is good (Alarm Will Sound's album of Aphex Twin), but most of it is awful (Vitamin quartet).

Hope that helps.

If you want a course, Robert Greenberg's How to Listen to and Understand Great Music - it's on Audible.

I would recommend Arthur Rubinsteins Chopin nocturnes. They are very minimal, and a perfect entry point into classical.