When bearded dragons are young they will usually eat 80% live food such as crickets, and 20% veg. As they grow older, that will slowly switch until your beardie will want 80% veg and 20% live food. This isn't always the case, as some bearded dragons have different preferences, but this is typically true.
Keep a constant supply of veg in the vivarium as they can't really over eat the stuff.
Then with juvenile bearded dragons offer them as many crickets as they can eat (with calcium and d3 powder sprinkled over them) 1-2 times a day in one serving.
With adults do the same, but only offer one all you can eat serving every other day.
You can feed them other live foods, but crickets are believed to be the more healthier option than mealworms. Also juvenile bearded dragons can struggle to digest the mealworms hard shells.