Creating a "meadow" depends on whether the "wildflowers" are really locally appropriate wild types (i.e., natives or close to it), or just showy annuals, biennials and perennials of all places of origin planted in a field setting for enjoyment and visual impact. If you want the real thing (more of a prairie-type planting, but with regionally appropriate species), I suggest a trip to the website of Prairie Nursery, and pull down under "Plant Information" to "FAQ’s" for site-preparation basics. An area can be prepared in many ways, from chemical defoliation to multiple tillings to solarizing (suffocating/cooking the existing vegetation)…and the prep can take weeks or more than a year. Again, depends what desired outcome you are seeking.
So start here, and then tell me whether we are talking a real wildflower meadow or something quicker or ???
I will also endeavor to find out who can help with this locally, by asking my pals over at Loomis Creek near Hudson.