The DE Africa Sandbox session automatically loads several folders of default notebooks. If you have accidentally deleted any of the folders or notebooks, they can be restored by restarting the server.
Save any open working files.
Select File -> Hub Control Panel. This will open a new tab.
On the new tab, select Stop My Server. The server will take a few minutes to stop.
When the server has stopped, the buttons will refresh. Select Start My Server.
Select Launch Server and Start.
This should reload all default folders and notebooks for the DE Africa Sandbox. Note that this will not overwrite files that have been added, renamed, or modified. Additionally, this only applies to default pre-loaded files and will not restore personal notebooks that have been deleted.