Subject headings link together books on the same topics or themes. For colonial Latin America, relevant subject headings include:
Colonists -- Latin America -- Social life and customs -- Sources
Indigenous peoples -- Latin America -- Social life and customs -- Sources
Latin America --History -- To 1830 -- Sources
Latin America -- Social conditions -- Sources
Latin America -- Politics and government -- To 1830 -- Sources
Spain -- Colonies -- America -- History -- Sources
The easiest way to find subject headings relevant to your topic is to find one source you like, and then check out its subject headings.