Hi

Best place to start is to learn the ropes from an experienced trainer, as there are so many things that can go wrong and land you in hot water with the authorities ;-) You have to have a owner's licence for a start, and read up on all the rules by the controlling body in your state.

Buy some greyhound books on Ebay (make sure it's australian version as training methods are very different overseas, plus different rules) and learn all about the history of the game, especially read on how top trainers fed and worked their dogs.

Common sense is a big necessity in training, knowing what your dog needs and knowing how to get the best out of your dog without overworking/underworking/overfeeding/underfeeding him etc and maintaining the best racing weight. There are rules on weight, if you present your dog for racing 2kgs too heavy or too light, you can be penalised for it.

Not as easy as it sounds, just going out to buy a greyhound, is it? lol ;-)

I would suggest that you buy a racing greyhound, leave it with a trainer, as you can learn a lot being an owner and going to the racetracks and listening to experienced folks.
Later on when you think you have gained sufficient knowledge, you could give it a go training your first dog. Make sure your first dog is an old hand, with plenty of starts (at least 30 or more) that way, the dog will teach you what to do! lol

However, you can also buy a pup, and leave it at the rearing farm to be reared with other pups in big runs so it can learn social and chasing skills. Then you can have the fun of waiting anxiously for its breaking in to start, to see if you have bought a good 'un or not!
cheers