A charcoal grill is mostly an airflow device. Nearly everything that separates a good one from a frustrating one is in the vents, the lid seal and how easy it is to add fuel without pulling the food off.
Vents are the temperature control
The bottom intake sets how hot the fire runs; the top vent stays open to keep the draught moving and the stale smoke out. Closing the chimney to lower the temperature is the most common beginner mistake and the fastest way to make food taste of creosote.