As admin I should see activities of all people not only those that belogs to mee.
That's your definition.

Kimai works slightly differently. Usually you only see the records of the current user. To see records of other users you have to use the filter options. Filtering by users is done via the small list in the bottom left corner. If you don't see a list there it's hidden (this is the case for older versions of Kimai). Move your mouse left of the customer list until you find something that changes to red. Then click it. Or simply update to a newer version.
Best Regards,
Severin Leonhardt