anyone know how to plant onions?

Sets (the little baby onions) are far easier than seed if it's your first go. Sunny spot, soil that drains well, push them in pointy end up so just the tip shows, about 10cm apart with rows maybe 30cm apart. Spring is the usual time, though there are autumn varieties meant to sit over winter. Birds love pulling them out in the first week or two. Just push them back in, or throw some netting over. Keep the weeds down, onions really don't cope with competition. They're ready when the tops go yellow and flop over. Lift them and let them dry somewhere airy for a couple of weeks before you store them.