Use Levels to control which level in the organization structure you are currently viewing on the sheet.
In most cases, you can only work with the data on one level at a time, and the level you select determines which level's data you are changing when you edit a sheet. On cube sheets, Levels is found among the other dimension selectors at the top of the cube sheet display, and looks similar to those other dimension selectors.
If you only have access to one level, Levels displays the name of the level to which you have access. If you change your current working level, and the sheet you are currently editing does not appear on the level you selected, you will be taken to the overview sheet on your new level, which lists all sheets available on that level. You can select a sheet to visit from this list.