The best way to describe modern art is really in the name. It’s art that steps away from the traditions of the past in favor of doing something new, fresh, and current. Sometimes it misses entirely but the point is that the artist is forging a new path and trying something interesting and that in and of itself can be amazing.
If you’ve never been to a modern art gallery you might actually get a little bit of comedic value out of it if the art doesn’t touch you in any way. Sometimes what the artists have created seems entirely pointless. I remember a trip to a modern art gallery where the piece on the wall was an entirely white canvas with a red dot in the middle. I was a teenager at the time and it was totally over my head but it was memorable enough that I still hold that memory and it makes me smile. Give a modern art gallery a try.