Webmail - Horde Preferences

After Login ...Go to the GEAR (center top)

Preferences -> Global Preferences -> Display Preferences
***set opening app

Preferences -> Global Preferences -> Locale and Time
***select language & timezone

Preferences -> Mail -> Message -> Deleting & Moving Messages
***Move Deleted to Trash (may need to create Trash folder)
***Purge Monthly

More Help with Horde:
Horde Wiki