Use it in open woods or fields. You want the deer to see it from a distance and come to investigate. Deer don't like to be surprised with another deer in it's face in thick woods.
I use grunt tube and/or rattling with it. First get their attention, then they see the deke to confirm what they saw. Or vise versa.
Take the shot when you have it, if you want to shoot that deer. Or just watch and see what happens. Some deer are spooked. Some are aggressive. Some don't care at all. I've had very alert does, aggressive bucks, and fawns that eat grass underneath it. I use a full body plastic deke. Looks real good, but somewhat noisy to put together, and too large to be carrying around. If you plan on using it more than once in same area, lay it down and cover it with leaves, etc. to hide it. Don't put scent directly on it, because you don't want deer investigating while it's laying under the leaves.
Some guys use cloths pins to simulate a spike buck, instead of the antlers that come with it. I'm sure you could do the same with the Montana Doe.
Face decoy quartering to you for a buck to approach head to head. Face quartering away if you have it as a doe, so buck will come downwind to butt end. 15-20 yards, should give you a 10-15 yard shot.
When it works, it's exciting. Depending on the deer, it will make or break your hunt. But, you will remember it.