You can think about it this way. The most distant thing in your scene is the sky/horizon. Choose a color and slide that saturation bar to the left. Then take that same color or something near it and slide the saturation bar to the right slightly. This gives you the first layer of distant mountains. Keep taking this approach to your colors as you come forward. Each layer will get more saturated and a bit darker/warmer. You can keep playing with both of those bars (saturation and light/dark sliders). The other thing to remember is as you come forward the items will get larger and more detailed as well. I hope this helps and gives you some ideas on what to practice and play around with.
Thanks so much incredibly helpful!
Glad I could help

