Queries are stored sets of instructions which can be used in a number of ways for different purposes. For example, suppose you want to look at girls names used in different families at different times; or look at at ages of death in certain countries in particular centuries; or find out how many of your ancestors died of a stroke: a query is what you need. You can use them to select pictures to view, mark boxes on diagrams, split files, and for other purposes. If you use spreadsheets, a common requirement is to use a query to extract data to copy into a spreadsheet, so that you can use your spreadsheet application to analyse the data and draw graphs.
To find out about queries, and how to use them, see Query Window.