In Excel 2010, click the "File" tab, click "Save As," and choose "CSV" as the file type. This method will save the topmost worksheet as a comma-separated values file.

Microsoft Excel offers many ways for you to manipulate and organize data, including using multiple "sheets" or tabs within the same spreadsheet file.

Then, click the Data tab and then click the Get Data option in the Get & Transform Data group. From the resulting submenu, choose From File and then choose From Excel Workbook.