This is age old guidance we authors receive over and over again. At least for as long as I've been writing my romances.
How am I supposed to show you? By using the five sense of my characters. What do they see, hear, taste, touch, and smell? So, rather than TELL you what the character is experiencing, I should SHOW you. This way you experience what they do.
How do you feel about that? Do you want to imagine why the characters crinkled their noses upon entering the house? Or would you rather be told directly that garbage and a decomposed body greeted them?
Personally, I believe show don't tell requires an author to trust the reader to understand the scene through the showing. So, the words I use are critical and requires deep thought and deliberate choices.
I find this a challenging concept, and I have a tendency to fall into telling mode too often. It's not that I don't trust my readers, because I do. I'm unsure whether I've shown what I intended for the scene in a thorough and concise way. Did I use the right word? Did I use the best word? It's a work in progress.
There are appropriate times for both showing and telling, so I must decide which works best for my story at a particular point. No one ever said writing is easy! I continually try to give you a story that transports you into the world and situations I've created. Trust me, I'm constantly learning more about the craft of writing!!