What should i feed my Bearded Dragon?

I Just bought a Bearded dragon from the pet shop and i'm not really sure what to feed him. He isn't a baby but he isn't a fully grown adult either.Now the guy from the pet shop gave me a tub of locusts but i think they're far to big, especially larger than the space between his eyes.I know your supposed to feed them fresh veg everyday but do i need to feed them crickets everyday too? Thanks :)