What should I feed my two to four month old baby?

"fruits" A two month old does not need anything other than formula or breast milk. The exception being a child with significant reflux needing cereal. Other than that consider starting solids at/after 4 months. From four months to a year a child will benefit from "fruits" which is any food that starts as a flower. This includes beans and other "vegetables". It has to do with digestive enzymes.
Breast milk, formula. Breast milk or formula will provide all the nutrition your baby needs at this age. Your feeding schedule will probably be more predictable with five or six feedings per day. Your baby should feed enough to wet a diaper every six hours or more. A few ounces of water or half strength apple juice may be an interesting diversion for a baby at this age, but solid foods are seldom helpful.