My soil sample is 3.7% organic matter. Is that good bad or ugly?
Lake County Michigan
"Organic matter in healthy soils can range anywhere from 5 percent to as high as 15 percent. Soils with less than 5 percent organic matter tend to be less productive, often promoting deficiencies in plant tissues. Organic matter may be added to soils through composting, including well-composted animal manure, chopped up leaves, grass clippings and organic mulches, or by planting cover crops."
The above is from "Building Healthy Soils for your garden" at msu.edu
You can also purchase compost at garden centers instead of making your own.
Spread 2-3 inches over the top of your garden and it will be gradually incorporated into the soil.
In the case of a lawn, you can simply spread it on the top or core aeriate your lawn and spread the compost afterwards so that some of it goes into the holes. You do not need to fill the holes.