I have some Peonie bulbs last fall. When should i plant?

https://www.gardenguides.com/139462-peony-planting-ohio.html

I would wait till spring and then be patient. They may need two years before they flower but in the meantime you’ll get lovely foliage and once they bloom, they will also multiply and pretty much thrive on neglect. Mine do!

Plant them when the soil is warm like in May.

In the fall. BTW, peonies don't have "bulbs" as their storehouse. The peonies packaging should have planting instructions on them. If you haven't, put them in a large, deep pot, with sterile loamy/sand soil rich in compost. Water good, don't let them sit in wet soil. Put in a cold area, an unheated garage would be perfect for them. Don't water unless really dry, and try not to let them freeze in the pot. You need to let them jumpstart the growing season. They missed out on the growth established in early fall & winter. As soon as the soil is workable in spring put in the optimal place in the garden, leave alone, but don't let them dry out, keep evenly moist, not wet, mulch helps retain moisture.

Don't expect gorgeous flowers for the first 3 years after planting. They need to mature, make, and store up food for 4th year bloom. Don't cut them back, pull out, move, or mow. There is nothing wrong with them, they are perennials, coming back every year, blooming from late April to early/mid June depending on the variety. They are very long lived, my neighbors have several over 50 years old. They planted them when first buying their house in the early 60's.

After established they are easily shared.

Lastly, if they have ants on the buds you will have better blooms. Leave them alone! If you plan on cutting bouquets, the ants are usually gone by full bloom. If not, a gentle shake upside down drops them off. They don't want to go in your house.

Would plant in the spring after frost is over