You can search for Files, Folders, People, and Sites.
Tap 
Search on the menu to search a full account, then tap to search for
Files, Folders, Sites,
or People.
Type your search text in the search box and tap Search on your device keypad.
Note: When
you're in Repository, Sites, Shared
Files and My Files a search box is available for you to
search for files within that area only.
All files matching the search are displayed. Tap a result to preview the file.
Tip: You can search for file names only, not for folder names. If you have Full Text Search
selected in Settings then all files containing
the search term are also displayed.
Note: Your previous searches are shown below the search box. You can tap on these to search
again.
The search results list is displayed until you click Cancel.