The My Documents folder opens.
Locate your spreadsheet and click the icon to the right or use the Edit option from the context menu. The file will open in the new tab.
Using filters and sorting your documents will facilitate the search of the necessary spreadsheet.
To open the file stored on your hard disk drive, first upload it to Documents clicking the Upload button in the upper left corner of the page.
You can also start a new spreadsheet right on the portal clicking the Create button in the upper left corner and selecting the Spreadsheet option from the drop-down list.