The most common method of planting is to broadcast spread your seeds. This is usually done by hand, but you can also use a lawn-type spreader.
After you have spread your seeds, rake the area over lightly. For seeds to germinate correctly they need to have good seed to soil contact, but you also don't want to bury the seeds too deeply. The general rule is to cover seeds to a depth no deeper than twice the seed's size. For example, if a seed is 4 mm in size, you would not want to bury it any deeper than 8 mm.
The seeds commonly found in a prairie matrix are usually small enough, that raking over the spread seed to mix and cover them with a thin layer of soil, is adequate.
If you are involving large numbers of people in the planting, a plastic cup full of seed (8 ounces or so) distributed over a square meter of soil is sufficient. As a possible side experiment, try varying the amount of seed you use at different locations in your parcel. You can then monitor growth and see to what extent the seed amount had on the overall growth of those areas.
If participants are each planting small manageable areas, you might want them to gently pat the soil down after their seeds are spread to insure good contact with the soil.
There is another method of planting that is becoming more and more common. It is planting using plugs. Plugs are unpotted growing plants of the varieties you choose, shipped or delivered in plastic bags. These plants can be planted directly into your parcel, and you have the advantage of knowing what is growing right from the start.
The critical thing to remember here is that the plugs will need to be planted quickly after you get them. Their roots are exposed, and if you delay planting, you may lose many individuals. If you use these, be prepared to plant them, since they can't be held for more than a day or two at the most.
One final consideration: I found that permanently staking out the entire perimeter of the parcel using small sections of pipe (metal or PVC) 6 to 10 inches in length and spaced every meter, insured that any quadrat could accurately be re-found for data taking and identification purposes. All that is required to re-grid your site is some string and some sticks or pencils.