Descriptive epidemiology studies and summarizes patterns of disease or of disease determinants in terms of time, place and person. The results are used to understand a population’s health status, generate hypotheses about the causes of diseases, and inform program planning and evaluation. In other words, descriptive epidemiology describes the distribution of disease (recall that epidemiology is the study of the distribution and determinants of disease in populations). This is done by describing a health outcome by different characteristics of person (race, age, or sex, for example), place (geographic location), and time (a specific year or a span of time). For example, the case fatality of cholera in 1854 in London was 40% (John Snow, cholera outbreak in London).
In a certain sense, public health surveillance may be considered as an ongoing descriptive epidemiological study and you may find may examples of ways to describe disease and determinants in terms of time, place and person in the articles on descriptive data analysis.