The fact he is eating at all is a good sign considering most dragons brought into a new home take up to 2 weeks to get adjusted. It sounds like you need to know alot of basic care information. Do a search on the web for bearded dragon care sheets and you will find a vast amount of links to read over. The basic requirements I will list below:
Cage: 4'x2'x2' or larger for adults (equal to 50gal breeder)
baby dragons to about 15" long, can be housed in a 20 or 35 gal tank.
Basking spot: 95-115 F, higher end for babies.
Ambient temp: 75-85 F day, 65-75 F night
Cool end of tank should be around 80F daytime, as low as 64F at night
Substrate: papertowels (non printed), butchers paper, newsprint, non stick shelf liner or plastic table cloth for babies and older. Adult bearded dragons can be housed on washed play sand. Do not use Calci-sand or any other sand that claims it's digestable.
Food: crickets, silkworms, butterworms or roaches no larger than space between dragon's eyes. Mealworms and superworms should not be fed to baby dragons and only as a treat for adults.
Greens: a mixed 'salad' of endive, escaroli, mustard greens, dandelion greens, collard greens (as stable) with other dark leafy greens and vegetables (peas chopped, stringbeans, carrots, summer squash, zuccini) sprinkled on top as variety. Fruits such as strawberries, rasberries, blueberries, melons can also be added as an occaisonal treat.
Dust insects once a day for babies, once every other day for sub adult and 2-3 times a week for adults with a calicum with D3 powder and a multi-vitamine powder.
Babies should be feed 2-3 times a day with insects and have finely chopped greens offered at all times. Sub adult dragons to adult should be giving insects 1-2 times a day, with salad offered constantly. Adults should only have insects 2-3 times a week, with salad offered every day.