You're writing a mental video...as well as a book.
The reader needs to see what is going on.
Sure you need to add a little explanation here and there. Usually, it's called backstory. With that, and character's thoughts and actions, depth is created.
But, would you rather have someone tell you about the movie they saw, or would your rather see it yourself?
The reader is the same way. Create the videos for them with your words.
How much is too much and how much is too little?
It's hard to say without reading the story. I was in a writing class once and the teacher said everyone needed to cut the extra explanations they were using in their stories. Except one person needed to add more. That was me.
But the difference in my writing and the others' stories could have been because I'd written poetry and non-fiction pieces for publication. I'd already learned to pare my writing way back, but not how to bring it into book length.