Well, the Baroque period was made up of more complex music, especially compared to the classical era. In the Baroque era, there were orchestras made up of a bunch of instruments. But then in the classical era, the most famous pieces were simple piano music. Not that Ludwig Van Beethoven's music was simple, but it was easier to follow than music from the Baroque period.
I hope this helps a little bit. Try to listen to Bach, and then Beethoven, and see the difference. Bach was part of the Baroque period, and Beethoven was part of the Classical period.
