Sorry Billy but I'm not sure about the owner telling you what you should or shouldn't be doing with the dog, maybe he should train it himself !!! In Vic mate you must be a owner/trainer for 12 months before you train for other people, that way you learn the basics on your own dog. Things will not work out to well if he is looking over your shoulder telling you what to do all the time!!!
First and most definatley foremost you should worm it out, have checked by a greyhound checker or vet, get some weight back on and build up some fitness before you look at public trialling. Breaking in is a very stressful time for young dogs and a fair percentage come home with worms,fleas, and soreness, don't be too eager to trial it mate make sure all is well with the dog first!!!