Step 10

Open the landscape 2 image and drag it into the main document using the Move Tool. Set this layer below the landscape 3 one.

Add a mask to this layer and use a soft black brush to remove the sky and the ground, leaving the mountains visible only.

Step 11

Create a Hue/Saturation adjustment layer and reduce the Saturation values to -88.

Step 12

Open the rock 1 image and cut out the rock only to add to the right of the main canvas. Set this layer below the rock 2 one and use a layer mask to remove the part covering the ground. 

Step 13

Make a Hue/Saturation values and change the Saturation settings to -78:

Step 14

Create a Curves adjustment layer and reduce the contrast and lightness until the details and texture of the rock disappeared completely to fit the misty background. 

Step 15

Open the rock 3 image and isolate it  to add to the left of the main canvas. Use a layer mask to remove the hard edges and blend the rock with the ground.

Step 16

Make a Hue/Saturation adjustment layer and change the Saturation values to -82:

Step 17

Add a Curves adjustment layer to increase the mist on the rock. On this layer mask, paint on the back side of the lower of the rock to keep some contrast there.

Step 18

Open the ruin 1 image. As it has a transparent background so just use the Move Tool to drag it into our working document and place it in the left of the rock 2 one. Add a mask to this layer and use a medium-hard black brush to remove most of the rocky ground and blend the ruin with the existing ground.

Step 19

Make a new layer (set as Clipping Mask) and use the Clone Tool (S) to remove and reduce some shadows on the columns 

Step 20

Create a new layer and use a soft brush with the color #c09d77, the opacity about 30% to paint on some details of the ruin to lighten the shadow and reduce the contrast of the ruin.

Step 21

Add a Hue/Saturation adjustment layer and reduce the Saturation values to -100:

Step 22

Make a Curves adjustment layer to darken the ruin.

Step 23

Create a new layer, change the mode to Overlay 100% and fill it with 50% gray. Activate the Dodge and Burn Tool (O) with Midtones Range, Exposure about 10% to refine the light and shadow on the ruin. You can see how I did it with Normal mode and the result with Overlay mode.