Download Lightroom presets and LUTs, absolutely free. Use the presets to add creativity and style to your photos.
Since the characters are in contrast with the background, mask out only the characters leaving the stick in between them using the Magic Wand Tool(W) and import them on to the working canvas.
To create a dull and rainy environment in the scene, import the image with thick grey sky and place it on the canvas as shown.
To make the scene more intense we need to create much more thick clouds. So import the clouds image and place it above the 'rainy clouds' layer.
To match the blue clouds to the scene, we need to desaturate the 'clouds 2' layer. With the 'clouds 2' layer selected Desaturate it to -61 using Hue/Saturation (Image > Adjustments > Hue/Saturation).