A spreadsheet is organized into a grid of cells, each identified by a column letter and row number (for example, cell B2 is column B, row 2); multiple related tables can live on separate sheets, or tabs, within one file. Entering data correctly matters more than it seems: a date typed as text won't sort chronologically, and a number stored as text won't total in a SUM formula, so recognizing and correcting data type mismatches is a core early skill. Basic formatting -- bold headers, frozen header rows, column width, and number formats like currency or percentage -- doesn't change the underlying data but makes a sheet dramatically easier for others, and your future self, to read and trust.