I am going to throw in another idea, since someone has woken this old thread. An idea I think way more fast and simple than some other ideas in the thread.
We have the tractor cutout and the building.
We make the tractor layer a Smart Object so that a) we keep the handles in their original corner locations, and b) because it is central to making this method work.
Note: I copied the foreground grass to a new layer at the top of the stack, so bottom of the tractor can be placed behind it.
The OP did not say how large the image should appear on the building, so I am going assume about 70% of the height of the building.
Double click the Smart Object to open in a new window so we can edit it, and add Relative 30% to the height of the canvas.
The bounding box will now surround an area relative to the full height of the building, and we can Ctrl/Cmd drag the corner handles into place keeping perspective close to spot on.
We can improve this in a couple of ways. 1) If you have Windows and Lazy Nezumi Pro, you can use its Vanishing lines preset to draw some accurate perspective lines as a guide. Note: I have a Curves layer which I have turned off in this screen shot. This was to temporarily increase contrast between the blocks and concrete pointing so I could more accurately position the lower Vanashing Line.
We can now get the perspective spot on when placing the tractor, and turn off the guide lines.
If you don't have Lazy Nezumi Pro, then a) I am sad for you, and b) use the grid graphic that we should all have in a CC Library. Open the SO to edit, and place your grid layer at the top of the stack. Use that to place the tractor on the wall. Open the SO to edit again, and turn off the grid layer.
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