As a developing empire, Spain settled the Caribbean out of a desire to exploit its perceived wealth. The journals of Christopher Columbus in particular were full of descriptions of the various resources (and peoples) that might be exploited for the benefit of the empire.
Spanish efforts at colonization focused on Puerto Rico, Hispaniola, and Cuba. On these islands, they conquered and exploited the labor of the indigenous peoples, at first for the purpose of mining for precious metals. This involved the enslavement of the region's peoples, who were often taken from island to island to work in an arrangement called an encomienda, which incentivized their exploitation. Disease, conquest, and the often brutal practices of Spanish settlers decimated the native populations of the Caribbean islands.
Over time, the economic focus of Spanish settlements became the cultivation of sugar, a highly labor-intensive crop. Spanish plantations increasingly turned to enslaved African people to work on sugar plantations. Caribbean islands also became way stations for Spanish ships that came from its colonies in the South and Central American mainland and a staging area for attempts to conquer and settle North America. The Bahamas in particular were rife with pirates and English raiders who preyed on ships laden with precious metals and other commodities.
Still, England did not really settle the Caribbean until the seventeenth century. English motives, like those of Spain, were essentially economic, and its colonies were primarily oriented toward the production of sugar. Wars with Spain resulted in English control of islands in the region including Jamaica and Barbados. Though neither had been central to Spanish plans for the region, Barbados in particular joined the group of centers of global sugar production. Under English control, the Caribbean would become the hub of a "triangular" trade that encompassed the Atlantic World—a supplier of sugar and a massive consumer of the enslaved people who toiled to produce it.