If it smells like manure then it is still manure. I would not use it except in a (huge) compost pile. If it smells very fresh when you stick your face into it, then it is compost and can be used freely without any harm to anything.

All you need is a light dusting, but since you have so much, you could spread 3 inches around and let it mulch over the rest of winter.

Sand would not necessarily help with drainage but mulching now with 3 inches of compost would definitely help with drainage by next spring.

Oh you lucky duck!

What does your soil need? If you are going to add manure to your soil you need apply only as much as the soil needs. However, given that manures can be storehouses for many disease pathogens it is always better to compost manure before applying it to the garden. You also want to put 3 parts of vegetable waste to 1 part manure when putting it onto your garden.

I have had large truckloads of manure like this dumped on my garden area. In fact, when I first moved to my current property, I made arrangements with a local trucker to bring semi-truck dump loads of manure in. I spread it about 18-21" deep, and let it sit for a couple months. The manure was already composted, so there was not much quick decomposition. However, the worms found the manure and went crazy in it, multiplying like mad, and mixing the manure with the soil underneath. I planted directly in the manure after this short wait, and had a fantastic garden. In areas where I did not walk on the beds, even though I did no tilling before dumping the manure, or after, the soil became quite loose, and you could easily push your hand well into the ground. A fast running hose would not leave puddles in the ground because the soil absorbed the moisture right away. The only other soil amendment I used was some gypsum to help remove some of the sodium that the manure had. Even where I did not use gypsum, the plants grew quite well, and I'm not sure that the gypsum helped, but it gave me some peace of mind. This kind of heavy manuring became my standard method of preparing a garden. I highly recommend it. I think that your 36" layer would work as well. On a related note, when I planted fruit trees, I put between 1500 and 2000 pounds of manure around each tree. The results were quite good. I especially appreciated that the soil was so permeable and water retentive. This property helped when there was a long period without rain. The trees continued to grow well without supplemental watering. By the way, in my area, manure is usually free for the hauling because it otherwise presents a waste disposal problem for dairies and feed lots. Even the fresh manure is a garden boon, since, applied as thick as I do, it composts in place if need be. I do not add extra materials to the manure for two reasons. First, it would massively increase the amount of work in preparing the garden since I would need to obtain the materials and mix them in. (I got about 450000 pounds of manure over about two months when I started one garden). Second, where I have made compost using manure and other materials, I do not see a difference between those areas and those with just manure. In a short while, the materials that fall on the manure from dead plants, and old crops can add any vegetable materials on their own. Regarding the smell: I used mostly cow manure, but also some horse manure. Once the manure is spread out, the smell becomes quite insignificant, if not non-existant after a week or so. I personnally don't mind the smell. I know what the manure is doing for the garden.
Renais

Renais, It's hard for me to grasp "garden area" and 450000 pounds of manure .
that must be some big garden area!

The best vegetable gardens I've grown were in a foot deep of straight, rotted horse manure. My experiences follow those of Renais, - spread the stuff out, water it a couple of times, wait a few weeks, and plant. The worms do the rest. I'd find a dozen huge worms in turn of the shovel.

The horse manure I use is a mixture of fresh and some older. I've found that 1" per year is right for my garden. Anymore than that with the mulch I add and the fertilizer levels go way high. I also use loose alfalfa as a mulch which can contribute too that also. But is composted a lot of the fertilizer values have went down. I added several inches of manure that has set for several years. So the age of the manure has a lot to do with it in my experience. We also use manure in farming around here. Like for it too age 18 months then add 3 inches. Jay

Renais: I am very, VERY jealous! LOL