That's some beautiful work.
The way you pose the question implies a simple 4 or 5 step answer
Do this, that, and that and that's how it's done.
Also they're not all processed the same either.
First of all these photos were posed and composed with to look the way they do.
Dramatic lighting, wide angle lens shooting up on the buildings, etc., were all planned out in advance.
In Photoshop these images like the first ones you posted were tinted to some degree, and darkened for effect.
Some are desaturated slightly.
I found an image and played around a bit.
Here's before and after.
I used Curves, Selective Color, Hue & Saturation, and Photo Filter adjustment layers.
Yeah! Adam Alex's photography and PP is amazing! No wonder he makes around £7000-8000 a wedding!!! I would say my most preferred processed image has to be Image 3, looking up the building. The shading and lighting on the building are awesome! Is that done why just simple curve levels, hue & saturation etc?