New documentation available at https://docs.openkm.com/kcenter/
The documentation at the https://www.openkm.com/wiki is definitivily deprecated.
Consider only use it, if you are user of OpenKM version 6.2 and older.
Click in the banner to close the warning.
Only users that have the role ROLE_ADMIN can access administration. A new tab Administration will appear for these users at the top right to access administration utilities.