Hey, how are things? How are things is a very common English expression. It means how are you?
How are things has three words that you need to remember. And again, it means how are you?
To answer this question, you can say, things are good, or things are fine, or things are great.
If things are not good, you can say, things aren't good, or things are okay.
This, again, is a very common everyday expression.
So how are things? Well, the sun is shining. I'm very happy today. So things are great.