Certified GKH Gardening Expert
They need to be planted in rich, well-draining soil in full to part sun. They are only hardy to zone 5, so try mulching well after planting. If you are following planting instructions, I would look to the bulb quality. Were they purchased from a reputable garden retailer? I might be leery if they were purchased late in the season on clearance. Also, some animals dig up bulbs. Check the soil and see if they are still there. Also, weather conditions may have caused the bulbs to rot.
Here is more:
https://www.gardeningknowhow.com/ornamental/bulbs/anemone/grecian-windflower-growing.htm
https://www.canr.msu.edu/news/where-are-my-bulbs-why-aren-t-they-flowering