Storing topsets is pretty easy. Just let them dry down like you would garlic or onions before storing them (on a screen or in mesh bags). I haven't used many in the kitchen because I have been planting the larger topsets and peeling the small ones is a pain - I could be doing something wrong, because they are supposed to be good for pickling. Just don't store them in something that does not allow air flow - they are not as dry as they seem.

The bulbs have stored ok for me for replanting in the fall or early spring but by spring they would not be worth eating (they resprout quickly). For eating I take the stalk (which is to one side of the bulb after producing topsets), pull it down to the plate of the bulb, break it off and with most of the dirty skins. Then I cut off the plate of the bulb (maybe the tip too) and squeeze toward the bottom. I then take the cleaned onions and freeze them in sandwich bags for easy use.

Hope this helps, best of luck!