Baby food is good to feed your grey, I feed mine some every morning in with a little oatmeal. I get the stage one vegetables like carrots, sweet potatoes or butternut squash, but green beans, peas and such would be good too. If you are introducing foods to a new grey you can offer them in most any form, raw, cooked or mashed. Try them different ways to see what they prefer and if they don't start eating them keep offering because one day the may eat some and like it.
A good pellet mix is needed, I recommend Harrison's High Potency formula and preferably the fine grind, they don't waste as much of it. You can offer them some off your plate at the evening meal just not anything salty or greasy. Mine loves any kind of pasta or rice and potatoes. Never give them raw potatoes, I am not sure why but have been told not to. This should get you started and some others may have more suggestions.