Basically....
You switch the camera to spot/centre metering so that it's on the minimum spread, or use a light meter. Then, look at your scene and pick however many areas you wish to shoot (about six or seven perhaps).
Stick the camera in aperture priority mode and pick an aperture (probably a small one like f11 or f22) and make sure you keep the aperture constant, along with the white balance and ISO (all should be manual). Point the camera at each of the six or seven areas and record the recommended settings for shutter speed for each of them.
Put the camera on a tripod and take one shot at each of the six shutter speeds you recorded, whilst NOT altering the aperture and ISO or other settings including focus and zoom/focal length.
Import the images to photoshop and use layers with selective erasing to reveal the areas of each picture you want. I tend to start with two images and two layers, erasing part of one, then flattening and using the next image until you are done.
That's one way... there may be a better one!!
Rob