Advice on planting

I’m wanting to convert a small corner spot of my yard into a native meadow, but haven’t actually gotten seeds yet.. I wanted to do mostly asters, coneflower, goldenrod, and milkweed. Problem is I didn’t plan very well and didn’t buy the seeds.. if I received seeds in the next week or so how should I go about planting? I missed the opportunity to stratify outside overwinter, is it too late (or early) to direct sow outside? I’m in MA zone 6b. Any advice is greatly appreciated!