Well, for BEST results, you need to sow them from seed and you'll get onions NEXT year. However, most people sow onion sets, which are little one-year-old onions. You need to loosen the soil and rake it out and then push the sets into the gound so that just the tip of the pointy bit is sticking out. I stretch netting over mine to keep the birds and cats off. You then need to keep an eye on them as sometimes the roots growing underneath can pop the set back out of the soil - just push them back in. Plant them about 25cm apart (the closer you plant them the smaller they'll be - plant them wider for bigger ones). I added chicken manure pellets and bone meal to my plot. Seemples ;-)