So you will want to read up.
First Check you heat!!! Don't set the lamp on the screen he will get burned and I do not want to see any more misshapen chams due to burns. Make sure you can keep your hand on the screen under the bulb without it burning. Then he is safe.
Next is food and supplements, stick to roaches and/or crickets with other insects in moderation. Don't over feed. An adult male is good with 5 to 6 lg cricket sized insects 3 times a week. Other wise they get fat and this causes health problems. Supplements calcium WITHOUT D3 every feeding but one a week, that day use a multi vitamin with D3. Very light dusting
Third is your UVB You need T5HO if you have the coil type it will not produce UVB deep enough to be effective for a cham sized cage. This is important to get right sooner than later.
Finally you cage is very small for a Veiled. 24x24x48 is minimum suggested, but if you can 36x30x48 is better. Males like to move around.
There is more of course. So as you read and learn you can ask more details