Explain how the Hadley Cell works

The Hadley cell is one part of the tricellular global atmospheric circulation of air. It begins at the equator, where intense solar radiation warms the air causing it to rise through convection. This rising air causes low pressure at the surface. As the air rises it cools and moves away from the equator, it then subsides or sinks resulting in high pressure in subtropical areas. 

Surface winds move from high to low pressure as part of the cell. These are called the trade winds that move from sub tropical areas to the equator. This happens on both sides of the equator and where the trade winds meet is called the ITCZ or Inter Tropical Convergence Zone.