How to Stratify, Store, and Plant Your Pawpaw Seed
Pawpaw seeds should be soaked for around a week and then then will need to be cold stratified. Stratification entails storing the seeds in a plastic bag with moist paper towels and storing the bag(s) in a cold, wet environment (a fridge or cellar will do - although watch for pests that might want a snack if you use a cellar) for 2-4 months. After the seeds have been stratified, you can plant them in the spring.
Take note that Pawpaws are deep-rooted species that are quite hard to transplant. So, ideally they should be planted directly in soil in their permanent home. Alternatively, they can be planted in a deep, narrow pot (minimum of 10 inches deep, and the deeper the better). A few months will pass before you see shoots begin to emerge, at which point the seedlings will do best in a shaded environment until they are mature enough to withstand the sun’s rays. If you've planted the Pawpaws in pot, you can place them in an area that doesn't receive full sun. If you've planted them in the soil, then consider suspending shade cloth above the seedlings for the first couple of months.
Recently emerged Pawpaw leaves
Close-up of a Pawpaw flower