At three months, he is still a baby (doesn't even rate a juvenile yet) so I would offer two different kinds of soft food fresh twice a day (once in the morning and again mid-afternoon) with dinner at sunset. Soft foods are just that, food that is soft - things like gloop (which you can continue to feed him for the rest of his life), polenta, couscous or pastina mixed with pureed veggies (baby food jars), birdy bread or muffin, etc.
Free-feeding seeds and/or pellets is the easy way of doing things but it's not really healthy for the bird regardless of what anybody else says. Parrots are hardwired to eat as much protein as they can (because, in nature, protein is not found in abundance or all the time and, as it is needed for life and, most especially, for breeding, nature gave them a 'protein tooth'

so, when they find a source, they eat and eat and eat until they can't eat no more) and, when you free-feed them a high protein food, you will not only end up with a bird that will have kidney (high uric acid) and/or liver (fatty liver or hepatic lipidosis) problems but you will also end up with a bird that is not eating enough produce because, given the choice, they will ALWAYS eat more protein than produce.