A worksheet in Excel is simply a big table in which you can freely enter your data.
When you start working with a new file (named: a “Workbook”), it contains 3 new worksheets (this is similar to a situation where a Word document will be opened with 3 pages).
To reach a certain page in a Word document you must scroll the document up or down; in Excel it is more simple: every worksheet has a small tab with its name, and to view it you must simply click the tab. (The initial names in a new file are: “Sheet1”, “Sheet2” and “Sheet3”).
The names can be easily changed, according to your need. For example, if every worksheet relates to a certain month, you can name them “January”, “February” and “March”. If they relate to departments in a company, you can name them “Sales”, “Administration”, and “Management”.
You can of course add more worksheets to a file, or delete existing ones.
Occasionally there is a need to have many worksheets with the same format, while they differ only in the data they contain (Or in other words - they have the same template). Therefore, instead of copying and pasting the formatting between all of them, you can “group” them and format them as one, and afterwards ungroup them and work on each one separately.