Get it a bag of bird seed that's specific to the breed at a pet store. And also to the other commenter, seeds ARE EXACTLY what birds eat
I give my conures and cockatiels seeds,parrot pellets(wild harvest is a good brand),fruit(diced mangos,seedless grapes and apples)and vegetables (steamed carrots and broccoli and cooked potatoes). Do not feed him:avocados,raw potatoes,drinking alcohol and other unhealthy foods.
Only a portion of your birds diet should be seeds, you should also offer fruits, veggies and even hard boiled eggs. You can find a list here of foods that are not safe.
seeds
What do conures eat?