I would put that in a bin and wait until it stop being warm to touch, but there could be a suggested waiting time. I use only starbucks coffee and it may be faster then manure. I bought a planting mix that had a lot of manure and it was suppost to be finished. It heated up in the ground, but the plants seemed ok anyway. If you put it on top, I don't think it would be likely to hurt the roots of a tree that are tougher the roots of small annual plants, but I would not add that without a wait time. The duration is debatable.

Concerning the garden soil question not sure if I would go for the sand or the topsoil. The topsoil maybe if I could get a look at it first. A lot of "top soil" that is sold isn't all that special. The manure and mulch sound ok.

If you want it done quickly I would either just top the beds off with compost and manure and then maybe till it in or just let it lay on top.

You didn't mention what you were planning to plant in the garden.

Concerning the compost question I assuming the manure is composted. If that's the case then top dress around the trees with compost and then mulch on top.

How about if I layer the first 6" to 1' with mulch, then put sand on top of that with the last 10" filled with garden soil.

Hi alvincowpasture,
Mix it all together....then plant....with all of that good stuff you don't need to layer anything,BTW...What kind of sand is it, decomposed granite is best (MHO) macrobes and microbes turn it into viable product,not so much with other sands...

Here's a little info on that...
Decomposed granite is a rock powder and is an excellent amendment for clay soils. All rock powders are great sources of minerals and micronutrients. All growing soils need them. As the microbes and macrobes like earthworms, digest the insoluble minerals, they break down into the various soluble micronutrients that all forms of plants need.

For example, limestone rocks are rich in calcium. Granite rocks are rich in potassium, etc. Seaweeds of course are the king of micronutrient fertilizers and soil amendments. There can be up to 70+ trace elements in seaweed. In locations where seaweed is not readily available; rock powders is one answer to the problem.

Research continues to reveal that insoluble tiny particles like rock powder minerals, can be easily digested or absorbed via microbial activity, over time, into the anatomy of growing plants, thriving in the presence of rich organic compost, and other forms of powerful biostimulants like aerobic compost teas.
Obviously a heavy clay soil is very difficult to initially dig, whereas a sandy loam is much easier. Heavy clay soils can be improved considerably by adding a lot of sawdust and mason's sand. DO NOT use beach or river sand! Mason's sand, being crushed granite, has sharp edges and actually loosens the soil.
One of the least understood aspects of gardening is that of capillary action of the garden soil. It is a proven fact that compressed earth has a better capillary action than undisturbed soil. That is why gardening books tell you never to walk between rows in a regular garden, as that encourages weed growth. And of course people are told never to step in a French Intensive bed and thus compress the soil.
But the capillary action is absolutely necessary to bring water up to the roots of growing plants to promote good and deep root growth. In regular garden rows, it is easy to roll a heavy 2 or 3 inch wide weighted wheel (mounted on an axle and handle) down the row directly over the freshly planted seeds, which will then promote deep root growth along that line. The spaces between the rows are than rototilled to eliminate footprints prior to the initial watering.
The basic concept of French Intensive gardening is that raised beds are created which have humus added, and the whole bed is light and fluffy to a depth of two feet to promote fantastic root growth. The beds are typically 4 feet wide and 12 or more feet long, with 3 foot paths between the beds.

Here is a link that might be useful: Mixing it all together ;-) Watch all nine video's

First dirt is what you track into the house and get yelled at for doing. What you grow plants in is soil.
People sell "garden soil", "topsoil", etc. all the time and you have no idea what it is you are really getting because it is the sellers idea of what that is. Good garden soil will be pat mineral (what most all soils have and that is the eroded part of the stones and rocks around us) and organic matter. Many people think that when they buy "garden soil" or "topsoil" they are getting loam and usually they don't. Loam is a specific soil composed of about 45 percent sand, 25 percent silt, 25 percent clay and about 5 percent organic matter and there is really very little of that and most of us do not have access to that.
There is no good reason to mix "topsoil", whatever that might be, with sand, unless the "topsoil" you get is clay and you will be mixing in 45 percent sand. Look around at diferent suppliers to see what they offer, ask for samples so you can actually see what they will deliver. Look at those samples closely to determine what you really want. One good, and easy, test to see what you might be getting requires one cup of soil which you put into a one quart clear glass jar. Fill that jar with water, cover (tightly), anad shake vigorously, and then let it sit for at least 24 hours. The mineral portion of the soil will settle out in bands according to the particle size and weight and since sand is the largest and heaviest any sand will be on the bottom with any silt the next layer followed by clay. Organic matter, if any, is the lightest and will be on the top. If the sample has no organic matter in it, or is mostly organic matter, walk away from that supplier.
Do not rely on the supplier to tell you what you need.