The green tops are edible. Chop them up and use as chives. You can freeze these as well to use for cooking later

When you get home, remove the tops from the onion bulbs.

Store onion bulbs on the counter

No need to "dry" or "cure" the onions. You can eat them right away or they will "dry" on their own on the counter

When the onions are at the end of their season, they loose their tops. You will see just onions sticking out of the ground. Make sure to pick them because they need to go at this point.