The largest thing to remember about winds is that they want to blow from warm areas to cold areas, aka from the equator to the poles. However, the coriolis force deflects the winds to the right in the northern hemisphere and to the left in the southern hemisphere. Because of this apparent deflection, the prevailing winds are broken into 6 distinct cells. The trade winds or easterlies are in the subtropics because the air is converging to around the equator and is being deflected to the right (only true in northern hemisphere) The westerlies are the ones which affect our weather while the polar winds also blow to the east like the Trade Winds. Hope this helps