The Minor League Overview screen (Team Menu >> Management section >> Roster Overview >> Minor League Overview tab) provides an overview of all of the affiliated teams in the selected organization's minor league system:

This screen is not available if you do not have minor leagues.

The top left corner of this screen displays a list of all of the teams in the selected organization's minor league system, and their current record, with links to their Team Home Screens. The bottom left shows the top prospects in the organization and how they are faring.

The right side of the screen is a list of all players in the selected organization's minor league system. You can take advantage of OOTP's Views and Filters, as well as many of the Common Drop-Downs and Common Action Menus. Review those sections to get a better understanding of how to manipulate the data on this screen to suit your needs.