Eric has a lovely thread detailing his experiment. Around the same time I was doing something similar but with a different goal. I purchased spawn, and spread it in layers. Burlap sack--spawn--woodchips/leaves/small soil clods/. Repeat. I made about a 4 foot layered pile. That was 2 sacks wide. About a month later I spread that burlap on top of flipped sod and covered with woodchips. 4 to 12 inches deep. The woodchips were from a local tree company, not shredded just chipped.
NC, however you're planning to progress, considering making a "compost tea". It can be super involved with molasses and finished compost and all that good stuff. Or it could simply be a 5 gallon bucket with a fish tank aerator and some grass, leaves, soil. Spread as needed, however is convenient. That should help kick start soil biology.